Learning on Amit Agarwal Linux Blog

Hackernews In Your Inbox

Sun, 25 Aug 2024 00:00:00 +0530

If you do not want to subscribe to any newsletter but still want to get some news delivered to you inbox then this post is for you.

First you need to get a script that can pull the hacker-news articles for you and you can find my script here. You can modify this script, specially the line: for id in trending_list[:50]: to change the number of posts that you would like to see in the mail.

Firefox addons for hacking

Sat, 23 Apr 2022 00:00:00 +0530

#Firefox addons

Here are some good and useful addons for hacking. I have mentioned some old addons which are quire good but not to be found on firefox addon site :(

Creating and using ackrc

Sat, 02 Apr 2022 00:00:00 +0530

ack is a fantastic replacement for grep and probably much more than grep. Here is what the dnf info has to say about ack

Name         : ack
Architecture : noarch
Summary      : Grep-like text finder
URL          : http://beyondgrep.com/
License      : Artistic 2.0
Description  : Ack is designed as a replacement for grep.

And their websites says -

Designed for programmers with large heterogeneous trees of source code, ack is written in portable Perl 5 and takes advantage of the power of Perl’s regular expressions.

mussh-run-commands-on-multiple-hosts

Sun, 06 Mar 2022 00:00:00 +0530

mussh allows you to run command/commands on multiple hosts at the same time. If you have farm of server setup with passwordless ssh or with same password (which is generally the case), then using mussh you can either check all the servers for some output or fix something or maybe update all the packages. How cool is that :)

Here is description of this package from dnf repo

Name         : mussh
Version      : 1.0
Release      : 18.fc35
Architecture : noarch
Size         : 20 k
Source       : mussh-1.0-18.fc35.src.rpm
Repository   : fedora
Summary      : Multihost SSH wrapper
URL          : http://www.sourceforge.net/projects/mussh
License      : GPL+
Description  : Mussh is a shell script that allows you to execute a command or
             : script over ssh on multiple hosts with one command. When possible
             : mussh will use ssh-agent and RSA/DSA keys to minimize the need to
             : enter your password more than once.

virt-install with cloud-init

Wed, 09 Feb 2022 00:00:00 +0530

If you have not heard about cloud-init then you should definately search for it and learn about cloud-config as well. You can find the documentation for cloud-config here. It is used for configuring VMs when running in cloud environments. Specially useful to inject the ssh keys or set the root password but you can do anything in the cloud-config as there is a section where you can run bash commands. While this is useful for cloud instances, you can make use of this feature when running your vm with qemu or libvirtd. All you need to do is either attach a iso disc with user-data and meta-data files in it or even simpler, you can use virt-install command. The command that I use is as follows

Stay safe from phising

Sat, 05 Feb 2022 00:00:00 +0530

Generally when you get a phising mail, the biggest challenge is finding if the site is genuine or not. And URL shortening services do not make it any easy. Earlier I had posted about using curl to expand the url in this post. However you might not be on a Linux terminal all the time (for example - you are checking something on your mobile), in that case what do you do?

Curl to exapnd short url

Sun, 09 Jan 2022 00:00:00 +0530

Many times I receive short urls in mail and other places like chats and messages. I first like to see the destination before I click on the url. I was looking for some way to do this in bash. I realized that this could be very simply done by looking at the Location header in the response from curl.

Example

`1`	`curl -I https://bit.ly/32WwCp4\|grep location`

and the output should be something like

Sleep infinitely in bash

Sun, 19 Dec 2021 02:38:57 +0530

I am sure that you would have got a lot of instances where you have wanted to sleep for infinity and ended up doing this

while [[ 1 ]]
do
	sleep 3600
done

or some other such similar loop to sleep for some time and wrap it in infinite loop.

I learned something new recently and found it very useful. You can do the above with

`1`	`sleep infinity`

and you can use that even for a while loop

Ignore case when completing file names in bash

Sat, 11 Dec 2021 02:38:57 +0530

Sometimes you don’t want to have the bash completion work with case completion. There could be several reasons like one I dont like is the default xdg folders starting with capital letters.

So, if you know that bash uses readline for a lot of configuration then there is a very easy solution, you can just run this command and start a new bash shell :)

`1`	`echo 'set completion-ignore-case on' >> ~/.inputrc`

Enjoy 👍

Warn when battery is low

Sun, 30 Aug 2020 00:05:57 +0530

I am very lazy to look at battery status and want to be warned when the battery is low. This means that even if I am away from the laptop, I can be warned that laptop is about to poweroff due to battery low. So, what kind of alerts I can have, many -

zenity message box
email
sms with twillio
Telegram message and possibility is endless.


LOW=35 ## This si the lowest percentage at which I want the alerts.
## Parse the acpi statue and decide if alert needs to be sent
per=$(/usr/bin/acpi -b | awk '{print $4}'|sed 's/%.*//') 

# source ~/bin/cron-scripts/sendsms.sh
if [[ $(/usr/bin/acpi |grep -c "Full\|Charging") > 0 ]]
then
    #This is when the AC is connected.
    exit 0
fi


if [[ ! -z $per && $per < $LOW ]]
then
    # sendsms "Battery is at $per%"
    export sub="Battery is at $per%"
    echo "Battery is running out : $per"|/usr/sbin/sendmail -t
    display_msg.sh "ACPI Warn" "Battery is at $per%"
    echo "ACPI Warn" "Battery is at $per%" | /home/amitag/bin/twilio-sms +919535210501
    zenity --warning --text="Battery is at $per%"
fi

Put this script somewhere and schedule in cron for every minute and enjoy.

Some good find alias.

Sun, 23 Aug 2020 11:05:57 +0530

Here are some interesting alias’s that you may want to add to your bashrc file or where-ever else you add your aliase’s. Very useful if you use find commonly.

There are four aliases defined here and have a comment explaining what it does. but these are so simple and useful that you probably dont even need the comments.


# ff:  to find a file under the current directory
ff () { find . -name "$@" ; }
# ffs: to find a file whose name starts with a given string
ffs () { find . -name "$@"'*' ; }
# ffe: to find a file whose name ends with a given string
ffe () { find . -name '*'"$@" ; }
# very very useful function: for finding files with ignore case, just type "f <part of filename>"
# This in combination with alias for 'g' is deadly.
#
f () { find . -iname '*'"$@"'*' ; }

Hope this is useful for you.

Books menu with bash

Sun, 16 Aug 2020 11:05:57 +0530

If you have a folder full of ebooks in various formats and not necessarily one sigle format and you want to have a quick menu to browse though your collection without requiring to open a File Manager then you are going to love this script.

The scripts works by allowing you to browse to the requied folder of your choice and once you select the file, then using xdg-open to open the file with your default viewer.

Podman repositories on ubuntu like distros

Sat, 01 Aug 2020 08:38:57 +0530

Recently I installed podman on ubuntu based dervative. I like podman a lot but to my distress I found that after installation, I was not able to search or run any containers. Found out that the repositories were not configured. So, if you run into such issues, then here is what you need to do. You need to create a file /etc/containers/registries.conf. And the contents of the file for just one docker hub registries would be -

Pygmentize Styles

Sun, 26 Jul 2020 18:38:57 +0530

I have recently started using pygmentize for looking at my code in terminal. A very good and native way to do this is to use pygmentize. If you do not know about pygmentize then

Highlight the input file and write the result to . If no input file is given, use stdin, if -o is not given, use stdout.

So, you can simply pass the script or source code through pygmentize and get a lovely color output with code highlighting in the terminal and this can be very useful.

scripting – performance improvement with file open

Mon, 20 Apr 2020 01:01:37 +0000

Sometimes just one line of code can make all the difference. I will show you with example.

Here is script with 2 functions. Both are writing some lines of text to a file. First function, “a” I have used the redirection to write to file. Function “b”, I have opened a file descriptor with “>” before going into the loop and use that reference for writing to the file. (This concept remains same for any scripting or programming language).

List all the tags for a image on docker hub

Mon, 16 Mar 2020 00:58:19 +0000

Something that you may want to know sometimes and docker cli does not show by default is all the tags for the image on docker hub. Here is example to list all tags fro the centos image

curl https://registry.hub.docker.com/v2/repositories/library/centos/tags |jq '."results"[]["name"]'

The example is for a v2 registry. The output for v1 is different than v2 registry. For a v1 registry, you can use command like below

curl https://registry.hub.docker.com/v1/repositories/centos/tags |jq '.[]["name"]'

kitty terminal themes

Mon, 09 Mar 2020 00:47:24 +0000

Kitty is a very nice and fast terminal that uses GPU, you can find more information here. For this terminal there are lot of themes available that you can checkout on the kitty themes github page here.

You can checkout the themes with

git clone https://github.com/dexpota/kitty-themes ~/.config/kitty/kitty-themes

Once you have done that, you can use the theme with adding a line in kitty.conf as :

include

unicode characters in urxvt terminal

Mon, 02 Mar 2020 01:00:31 +0000

If you quickly want to type the unicode character in urxvt terminal, then try doing this:

Press Shift+Ctrl and then type the number for the unicode. 🙂

Get the git url of current repo in clipboard

Mon, 30 Dec 2019 01:04:29 +0000

Lot of times, I just want to copy the git url to clipboard. This is so common in my flow of work that I created an alias for it. Here it is:

alias git-url="cat .git/config|awk '/url/ {print $3}'|xclip -i -selection clipboard"

Script to try various themes from kitty terminal

Mon, 16 Dec 2019 00:55:06 +0000

Here is the script. Very simple yet very useful script.

#!/bin/bash - 
#===============================================================================
#
#          FILE: kitty-theme.sh
# 
#         USAGE: ./kitty-theme.sh 
# 
#   DESCRIPTION: 
# 
#       OPTIONS: ---
#  REQUIREMENTS: ---
#          BUGS: ---
#         NOTES: ---
#        AUTHOR: Amit Agarwal (aka),
#  ORGANIZATION: Individual
#       CREATED: 12/06/2019 10:15
# Last modified: Fri Dec 06, 2019  10:41AM
#      REVISION:  ---
#===============================================================================

set -o nounset                              # Treat unset variables as an error

FOLDER="/git/terminal.sexy/dist/schemes"  ### This is git folder where you have terminal.sexy cloned

if [[ ! -d $FOLDER ]]
then
    cd $FOLDER/../../../
    git clone https://github.com/stayradiated/terminal.sexy

fi

cd $FOLDER
tmp=$(mktemp /tmp/color-XXXXXXXX)
echo $tmp
files=$(find . -type f -name \*json)
for line in $(echo ${files[*]})
do
    echo "Processing $line"
    >$tmp
    echo "# From $line.. processed by Amit Agarwal script" >> $tmp
    sed -n -e '/color/,/\],/ p' $line | sed -e 1d -e '$d'| \
        sed 's/[",]//g'|awk '{count++; print "color"count"\t "$1}' >> $tmp
    grep ground $line |sed 's/^ *//' |sed 's/[":,]//g' >> $tmp

    kitty @ set-colors -a $tmp

    ls --color=auto ~
    read -p "If you like the theme, just press l ::" test
    if [[ $test == "l" ]]
    then
        rm -f ~/.config/kitty/theme.conf
        cp $tmp ~/.config/kitty/theme.conf
    fi
done
rm -f $tmp

i3 – show mapped hotkeys

Mon, 02 Dec 2019 01:05:19 +0000

Here is a simple script that can show you the hotkeys bound in ~/.config/i3/config :

#!/bin/bash - 
#===============================================================================
#
#          FILE: i3-showkeys.sh
# 
#         USAGE: ./i3-showkeys.sh 
# 
#   DESCRIPTION: 
# 
#       OPTIONS: ---
#  REQUIREMENTS: ---
#          BUGS: ---
#         NOTES: ---
#        AUTHOR: Amit Agarwal (aka)
#  ORGANIZATION: Individual
#       CREATED: 11/26/2019 14:22
# Last modified: Tue Nov 26, 2019  02:43PM
#      REVISION:  ---
#===============================================================================

set -o nounset                              # Treat unset variables as an error


> /tmp/keys
cd ~/.config/i3
grep '^bindsym $mod' config|grep -v '^#'|grep -v 'move container to'|grep -v 'workspace $ws'|sed 's/bindsym //'|grep -v '='|while read key line
do
    printf "%20s\t?\t%s\n" "$key" "$line"  >> /tmp/keys
done

xterm -e "cat /tmp/keys; read -p 'press any key to continue'"
rm -f /tmp/keys

And once this is done, you can bind the script in i3 config like this:

check hard disk rpm or rotation speed

Mon, 23 Sep 2019 01:00:50 +0000

Lot of times you want to check the disk rpm, especially on the servers to check if it is 7.2K or 10K or 15K rpm disk. How do you do this from linux terminal. Here it is :

sginfo -g /dev/<device>

Note that sginfo comes from sg3-utils.

ssh trick – ssh to remote host with bastion host

Mon, 16 Sep 2019 00:55:20 +0000

Lot of times, you have to ssh to a server with bastion host. If you dont know what is bastion host then see this:

Now, in such cases, either you add an entry in “~/.ssh/config” to route the ssh through the bastion host or do ssh to bastion host and then ssh from there to the actual host. But wait, there is always a better way:

Check your session type – wayland or X11

Mon, 15 Jul 2019 00:51:43 +0000

With both wayland and X11 in mainstream, its pretty easy to forget if you are running in Wayland or in X11. To check this here are the commands:

loginctl list-sessions
# The above command will show you all the sessions. Note the session number for your session

loginctl show-session <session number> -p Type

Running dnsmasq with NetworkManager in Fedora

Mon, 10 Jun 2019 01:00:04 +0000

Here is a good link to do this:

https://fedoramagazine.org/using-the-networkmanagers-dnsmasq-plugin/

Split pcap to multiple files based on number of packets

Mon, 03 Jun 2019 01:00:38 +0000

Here is a script that can use tshark to split a large pcap to multiple small pcaps

inpcap="test.pcap"

max=$(tshark  -r $inpcap -n -T fields -e frame.number|tail -1)

# This is the number of packets in each split pcap
c=1

# Save all new pcaps to out, if it does not exist, create it.
[[ ! -d out ]] && mkdir out

for i in $(seq 1 $max $c)
do
        tshark  -r $inpcap  -n -c $c "frame.number==$i" -w out/$i.pcap
        #Do other stuff, if required
        read -p "Send the next packet? "
done

A very simple 3-4 line script that has saved my day so may times.

copy /proc folder

Mon, 18 Mar 2019 01:03:37 +0000

Other day, I was trying to copy the proc folder with following command:

tar cvzf /tmp/proc.tgz /proc

and I found out that all the files in tar were empty. Strange it may seem but lot of people are facing this as /proc is not a regular filesystem, so I wrote a quick script to copy the proc folder. Here is the script:

cd /
mkdir /tmp/proc
[[ -z $1 ]] && exit -1
find /proc/$1/ -not -name pagemap | while read F ; do
    D=/tmp/$F
    if [[ -d $F ]]
    then
        echo "$(ls -ld $F) => Directory"
        mkdir -p $D
    fi
    if [[ -L $F ]]
    then
        echo "$(ls -ld $F) => copied"
        cp -P $F /tmp/$F
        
    elif [[ -f $F ]]
    then
        echo "$(ls -ld $F) => Cat"
        cat $F > /tmp/$F
    else
        echo "Dont know $F"
    fi
done

cool sed/grep magic to convert output to csv format

Mon, 11 Mar 2019 01:12:34 +0000

I generallly keep doing this a lot, so thought will share with you. Lets assume we are capturing free ouput every min/hour/or whatever. The output looks like this:

Time: Mon Jan 21 23:59:10 AEDT 2019
——————-

total used free shared buff/cache available
Mem: 32014 8656 1735 1697 21621 21308
Swap: 51195 75 51120

then we can use some grep and sed to convert this to something like this:

Mon Jan 21 23:59:10 AEDT 2019,32014,8656,1735,1697,21621,21308

bash function for rpm whatprovides

Mon, 31 Dec 2018 01:00:38 +0000

Sometimes some simple one-liner function can save you a lot of time, like-

wps ()
{
    rpm -q --whatprovides $(which $1 )
}   # ----------  end of function wps  ----------

xev – Check the X keyboard events

Mon, 19 Nov 2018 01:00:26 +0000

xev man page

xev – print contents of X events

So other day I was checking why my play key was not working and wanted to check if it maps to one of the X default mappings for the keyboard and was stuck on how to check this. And finally found that I can try this:

xev -event keyboard

Pretty neat 🙂

ranger – try terminal file manager

Mon, 11 Jun 2018 01:00:06 +0000

ranger is a terminal file manager, just install and run and have some fun.

Tip: You might want to try it on uxrvt terminal and in Photos folder once.

Name : ranger

Version : 1.7.2

Release : 8.fc28

Arch : noarch

Size : 1.2 M

Source : ranger-1.7.2-8.fc28.src.rpm

Repo : @System

From repo : fedora

Summary : A flexible console file manager

URL : http://savannah.nongnu.org/projects/ranger/

License : GPLv3+

Description : Ranger is a free console file manager that gives you greater flexibility and a

good overview of your files without having to leave your *nix console. It

visualizes the directory tree in two dimensions: the directory hierarchy on

one, lists of files on the other, with a preview to the right so you know where

you’ll be going.

Display IP address in console login screen

Mon, 30 Apr 2018 01:02:44 +0000

Here is one liner that will add the current IP address in the console login screen (if you are not running X as is case for servers):

(ip -o -4 a| awk '$2 !="lo" {print "\nIP Address ::"$4}' |tr '\n' ',';echo)>>/etc/issue

Just execute the above command as root. It will add the required code in “/etc/issue” to display the IP address. BTW, you can also use “\4” or “\6” instead of that command to get the IP but that will not work with some old versions of Linux.

Port php mysql scripts to php 7.0 from 5.x version

Mon, 23 Apr 2018 00:56:57 +0000

Recently I got a script or series of scripts that were written for PHP 5.6x and hence used mysql_connect which as you know by now does not work with PHP 7.0. Since there were number of scripts, I thought it would be waste of time to change them manually and wrote a script to fix them. If you have similar situation then probably this few lines could help you.

Since my scripts did not use all the functions so I did not put the sed commands for all of them but you get the idea 🙂

Monitor progress of coreutils commad like mv, cp etc

Mon, 02 Apr 2018 01:00:41 +0000

Monitor progress of coreutils commad like mv, cp etc

You can use command called “progress”. Other option is “pv” but that is little complicated so here is simpler option.

Progress – A Tiny Tool to Monitor Progress for (cp, mv, dd, tar, etc.) Commands in Linux

To install, you can do the following:

dnf install progress

Send history of current host to some other host over ssh

Mon, 26 Feb 2018 00:44:11 +0000

Sometimes I want to save the history of current host on another host. This is to ensure that I can use copy/paste on other host to run the commands. To this, I found a simple solution –

history| ssh <user>@<host> 'cat - > /tmp/history'

And on the new host, you can find the history in file “/tmp/history”, cool :). Now I can quick edit this file to create this as shell script as well if required. How cool is that.

Fix display size on libvirt/Qemu guest

Mon, 22 May 2017 01:05:14 +0000

Lot of times I find myself of VM that does not correctly resize the screen display and that is literally nuisance. So, here is quick and dirty fix for this.

First you need to find out information about your display with following command:

xrandr -q

And you will see output like this:

Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192
Virtual-0 connected primary 1920×1080+0+0 0mm x 0mm
1024×768      59.92 +
1920×1200     59.88
1920×1080     59.96*
1600×1200     59.87
1680×1050     59.95
1400×1050     59.98
1280×1024     59.89
1440×900      59.89
1280×960      59.94
1280×854      59.89
1280×800      59.81
1280×720      59.86
1152×768      59.78
800×600       59.86
848×480       59.66
720×480       59.71
640×480       59.38
Virtual-1 disconnected
Virtual-2 disconnected
Virtual-3 disconnected

Getting Started with Elixir Programming Language

Mon, 15 May 2017 01:10:11 +0000

If you have been reading blog posts, hacker news threads, your favorite developers tweets or listening to podcasts, at this point you’ve probably heard about the Elixir programming language. The language was created by José Valim, a well known developer in the open-source world. You may know him from the Ruby on Rails MVC framework or from devise and simple_form ruby gems him and his co-workers from the Plataformatec have been working on in the last few years.

Fix weird flux menu

Wed, 03 May 2017 02:03:27 +0000

Some distro’s just add all the items under single menu and thus the menu itself becomes unusable because of the number of items in the submenu and this I did not like and hence ceated this simply python script to fix that. For using the script, back up you “menu” file, redirect the output of this script to ‘menu’ file again.

#!/bin/python

F = open("~/.fluxbox/menu", "r")
count=0
mkc=1
started=0

for line in F:
    print line.rstrip()

    if '[submenu]' in line.lower() and started == 1:
        print '[end]'

    if '[end]'  in line.lower():
        count=0
        mkc=1
        if started > 0:
             started=0
             # print "Count is {}".format(count)
             # print "Started is {}".format(started)
             print '[end]'
    if '[exec]'  in line.lower():
        if count > 15 :
            if started > 0:
                started=0
                print '[end]'
                # print "Count is {}".format(count)
                # print "Started is {}".format(started)
            print '[submenu] ({})'.format(mkc)
            started=1
            mkc+=1
            count=0
        # print count
        count+=1

scapy packet dump to packet

Mon, 10 Apr 2017 01:05:34 +0000

First you need to have scapy installed. And if you don’t know about scapy, then

Scapy is a powerful interactive packet manipulation program. It is able to forge or decode packets of a wide number of protocols, send them on the wire, capture them, match requests and replies, and much more. It can easily handle most classical tasks like scanning, tracerouting, probing, unit tests, attacks or network discovery (it can replace hping, 85% of nmap, arpspoof, arp-sk, arping, tcpdump, tethereal, p0f, etc.). It also performs very well at a lot of other specific tasks that most other tools can’t handle, like sending invalid frames, injecting your own 802.11 frames, combining technics (VLAN hopping+ARP cache poisoning, VOIP decoding on WEP encrypted channel, …), etc

Kernel dropped packet analysis

Mon, 27 Feb 2017 00:30:26 +0000

Found a simple method to check for all the packets dropped by kernel.

First you need to install dropwatch with

dnf install dropwatch

and details of the package

Name        : dropwatch

Arch        : x86_64

Epoch       : 0

Version     : 1.4

Release     : 13.fc24

Size        : 27 k

Repo        : fedora

Summary     : Kernel dropped packet monitor

URL         : http://fedorahosted.org/dropwatch

License     : GPLv2+

Description : dropwatch is an utility to interface to the kernel to monitor for dropped

network packets.

Get kernel function name from kernel address.

Mon, 13 Feb 2017 01:14:01 +0000

If you are using pmap or using strace and want to covert kernel address to function name then you can use the following technique.

First you need to install elfutils, if not installed.

dnf install elfutils

and after this you can use the following command

eu-addr2line -f -e /boot/vmlinuz-$(uname -r) <addr>
#Example
eu-addr2line -f -e /boot/vmlinuz-$(uname -r) 00007f36a8045000

Compose a video from a text sequence

Mon, 23 Jan 2017 01:16:36 +0000

I came across this useful and interesting project so sharing with all of you:

seq2vid

xsos – a tool for sysadmins and support

Wed, 24 Aug 2016 00:31:24 +0000

Here is a very nice article that you may find useful

https://access.redhat.com/discussions/469323

git – plot the history

Mon, 23 May 2016 00:38:12 +0000

git has a very simple solution to see all the commits in a graphical form. If you need to understand all the commits history all you need is

git graphviz|dot -Tpng  -o /tmp/a.png

This will generate a file called /tmp/a.png which will diplay the complete commit history.

DNS – simple and effective guide with history

Mon, 15 Feb 2016 01:09:00 +0000

Here is link to a very nice and definitive guide to DNS. Very detailed and useful. There is a pdf version as well to download 🙂

https://webhostinggeeks.com/guides/dns/

Thanks to Andrijana Nikolic for providing a valuable resource to share with you all.

virsh – show ip address of all running VMs

Mon, 01 Feb 2016 00:52:31 +0000

If you are using the libvirt and associated tools, then you must be aware about virt-manager. However this being a GUI tools, it is not possible to always use this. “virsh” is a good option for this.

To start with, if you need to know all the VMs all the running VMs, then you can use (to only view the names):

virsh list --name

Extending this to make it more useful is the case if you need to know the IP address for the running VMs. Here is a simple code that you can put in alias or function that can be used to get the IP address of the running VM’s.

Disk usage by file type

Mon, 30 Nov 2015 00:51:20 +0000

Trying to find the total usage for each of the file types by extension, then here is a quick bash function for you :

disk_usage_type () 
{ 
    find . -name '*'$1 -ls | awk '
    BEGIN{
        a[0]="Bytes";
        a[1]="KB";
        a[2]="MB";
        a[3]="GB";
    }
    {sum+=$7; files++;}
    END{
    print "Total sum is ::\t" sum;
    print "Total files  ::\t" files;
        while (sum > 1024) {
            sum=sum/1024;
            count++;
            };
        print sum" "a[count];
    }'
}

Just define the function in one of your bash startup files. After that to use the function pass in the extension for which you would like to find the total size. Output should be something like below:

terminal, terminal everywhere.

Mon, 23 Nov 2015 00:47:12 +0000

Tilda is a borderless terminal that can be started multiple times each with its own configuration.

Name        : tilda

Arch        : x86_64

Epoch       : 0

Version     : 1.2.4

Release     : 1.fc23

Size        : 344 k

Repo        : @System

From repo   : fedora

Summary     : A Gtk based drop down terminal for Linux and Unix

URL         : http://github.com/lanoxx/tilda

License     : GPLv2+

Description : Tilda is a Linux terminal taking after the likeness of many classic terminals

from first person shooter games, Quake, Doom and Half-Life (to name a few),

where the terminal has no border and is hidden from the desktop until a key is

pressed.

Executing commands on multiple hosts

Mon, 21 Sep 2015 00:33:38 +0000

If you have to execute the same command in multiple hosts, then you can use mussh:

Description : Mussh is a shell script that allows you to execute a command or script

over ssh on multiple hosts with one command. When possible mussh will use

ssh-agent and RSA/DSA keys to minimize the need to enter your password

more than once.

First install mussh with the following command

dnf install mussh

Now to run this for multiple hosts, you can run like this

retext – Editor for restructured text

Fri, 15 May 2015 01:04:50 +0000

restructured text is a simple text editor for markdown/restructured text which can show preview as well. So, here is some details on same :

Name        : retext
Arch        : noarch
Epoch       : 0
Version     : 5.0.1
Release     : 7.fc22
Size        : 412 k
Repo        : @System
Summary     : Text editor for Markdown and reStructuredText
URL         : http://sourceforge.net/p/retext/home/ReText
License     : GPLv3+
Description : ReText is a simple but powerful text editor for Markdown and reStructuredText.

ionice – renice you IO activity for the process.

Mon, 13 Apr 2015 07:10:29 +0000

ionice is utility provided by the package util-linux. Description of util-linux:

Description : The util-linux package contains a large variety of low-level system

utilities that are necessary for a Linux system to function. Among

others, Util-linux contains the fdisk configuration tool and the login

program.

With the help of this utility, you can set the scheduler priority for your IO scheduling upto RealTime, but be careful that can make other process sluggish. Example use:

Fedora/Ubuntu issue with assigned IP by dhcp server.

Fri, 13 Mar 2015 00:40:51 +0000

In the recent versions of Fedora/Ubuntu, I found that if the DHCP server assigns a reserved address, the address is not applied to the system. Finally I found that adding the below in /etc/dhcp/dhclient.conf, would fix the issue.

send dh-client-identifier = hardware;

ssh authorized keys – limit ssh session to custom command

Wed, 04 Mar 2015 00:34:21 +0000

If you want a ssh key to be able to run a custom command only and nothing beyond that, then you can use the “command” option in the authorized_keys file of ssh.

For example, to limit user to run only top command with a key, you can add the key like this:

echo 'command="/usr/bin/top" ssh-rsa ' >>~/.ssh/authorized_keys

script to get hard disk health in fedora/ubuntu

Mon, 01 Dec 2014 12:12:08 +0000

First, put this in a script.

#!/bin/bash

#Change as appropriate
HDD=sda

export sub="SmartCtl data for HDD"
echo 'To: &lt;Your Email&gt;
Sub: [Cron] $sub
MIME-Version: 1.0
Content-Type: text/html
Content-Disposition: inline

&lt;html&gt;&lt;pre&gt;'


echo '&lt;style&gt;

hr {
    display: block;
    height: 1px;
    border: 0;
    border-top: 1px solid #ccc;
    margin: 1em 0;
    padding: 0;
}
&lt;/style&gt;
'

echo '&lt;h2&gt;Errors on HDD:&lt;/h2&gt;'
echo '&lt;hr&gt;'
sudo smartctl -l error  /dev/$HDD
echo '&lt;h2&gt;Health of HDD:&lt;/h2&gt;'
echo '&lt;hr&gt;'
sudo smartctl -H  /dev/$HDD

echo '&lt;h2&gt;Detailed info&lt;/h2&gt;'
echo '&lt;hr&gt;'
sudo smartctl -a -d ata /dev/$HDD

echo '&lt;h2&gt;Journalctl output for smartd&lt;/h2&gt;'
echo '&lt;hr&gt;'

if [[ -f /etc/fedora-release ]]
then
journalctl -x --show-cursor -u smartd --since=yesterday
else
#This is for Ubuntu.. still using dmesg

dmesg -T -l err,crit,alert,emerg

fi


echo '&lt;h2&gt;All Details&lt;/h2&gt;'
echo '&lt;hr&gt;'

sudo smartctl --xall /dev/$HDD


echo "Thanks for using Amit Agarwal's script"
echo '&lt;/pre&gt;&lt;/html&gt;'

and then put this in cron:

ncurses based eFTE editor – programmers lightweight editor

Mon, 17 Nov 2014 01:15:49 +0000

nefte is a lightweight programmers editor. Here is descriptioin:

Description : eFTE is an advanced programmers editor with goals of being lightweight, yet
            : totally configurable. Support for user defined programming languages, menu
            : systems and key bindings are provided with many common defaults already
            : defined. eFTE is still a new project, however, we extend from the FTE editor
            : which was first released in 1995, so eFTE is tried and true with many features
            : for the programmer/text editor.
            : 
            : This package contains nefte, the ncurses version of the editor.

And to install:

Multiple entry in .ssh/config file

Fri, 24 Oct 2014 00:24:29 +0000

Here is a link to one post on ssh config file.

However, if you want entries for lot of servers with their IPs or names, then it could be cumbersome to add all the entries in the .ssh/config file. So, here is a shortcut notation:

Host 1 2 3 4 5 6
Hostname 192.168.1.%h
    User 
    
    Ciphers arcfour

where '%h' denotes the IP that you use in the ssh command.

The following escape character substitutions will be performed:
             ‘%d’ (local user's home directory), ‘%h’ (remote host name), ‘%l’ (local host name),
              ‘%n’ (host name as provided on the command line), ‘%p’ (remote port),
              ‘%r’ (remote user name) or ‘%u’ (local user name).

Debuggging bash cron scripts.

Mon, 01 Sep 2014 00:44:36 +0000

I have to several times debug scripts that I get complain about working when logging in normally but they do not work when run in cron mode. So, quite a lot of times, redirecting the stderr of the script is all that is required to see what is happening, but sometimes that just does not help if the script is calling another script which is mis-behaving and under lot of other conditions. So, how to at-least take a look at why these are failing, login with ssh.

ldap search function

Mon, 25 Aug 2014 00:42:04 +0000

First you will need the ldap search utility. The client for ldap search comes in openldap-clients, so you need to install that first:

sudo yum install openldap-clients

Now, that you have installed it, try to find something in some open ldap server, example:

ldapsearch -LLL -h  db.debian.org   -x  -b "dc=debian,dc=org" "cn=Joao*"

This should list couple of entries for you. Now, that you have ldapsearch working, lets define a function in .bashrc file:

rfc2html – php script to view rfc with index and links.

Mon, 21 Jul 2014 01:26:32 +0000

If you have to keep viewing RFC’s and you miss index and links in RFC while viewing rfc, then you should check-out rfc2html. It is scrtip that takes plain text rfc and converts it to html.

You can get the original code from sourceforge.

However, I found some small issues with the script and have sent a mail to the authour about the same. In the meantime, you can use the diff below to fix the issue’s or download this diff file rfc2html.diff and apply the diff:

Some nice linux tutorials

Mon, 05 May 2014 00:45:28 +0000

Some very nice articles and tutorials on Linux, find here. Pretty nice collection.

get the contents of whole site like some wiki or wikia

Mon, 24 Feb 2014 01:08:14 +0000

For wikis and wikia, generally if you are trying to get some url mirror, then websucker.py is an excellent option. This script is in the python sources so, to get this tool,

yumdownloader --source python

Install the rpm downloaded in current directory and then go to ~/rpmbuild/SOUURCES. You should find a Python-*.tar.xz file here, just extract with

tar xvf Python*.tar.xz

and there you go, you should find the tool in Tools/webchecker/websucker.py.

inotify -watch for file to change

Tue, 28 Jan 2014 00:41:45 +0000

Here is a simple command for you. It uses inotify tools. So first you need to install :

sudo yum install inotify-tools

and then you can try something like this:

while true; 
do 
inotifywait -r -e modify --exclude=".swp" . && make; 
done

Here, once the file changes, we are running make, but you can do anything you want.

cgroups – use to control your cpu and memory

Mon, 06 Jan 2014 00:33:23 +0000

cgroups is a kernel feature and with userspace utilities, we can use the feature to control the cpu and memory for per process. So, lets first install the required tools.

sudo yum install libcgroup-tools

Now, we need to enable the service.

sudo systemctl enable cgconfig.service
sudo systemctl enable cgred.service

cgconfig.service is to enable configuration for cgroups and
cgred.service is to enable configuration for cgroups for processes depending on the name.

Fix typescript files generated with script command

Wed, 18 Dec 2013 00:40:45 +0000

Generally quite a lot of us would have used the script command. This generates the logs for the session. But the problem with the logs is that it contains a lot of un-readable characters. These characters are mostly from the color codes, and as such can be removed very easily with a single command:

cat typescript | 
 perl -pe 's/e([^[]]|[.*.*?[a-zA-Z]|].*?a)//g' | col -b > typescript-processed

This assumes the input log file is named as typescript and the output is kept as typescript-processed. You can change the names as required.

LibreOffice – Formulae Auditing

Thu, 30 May 2013 01:03:56 +0000

If you have a excel sheet with lot of formula’s and you are trying to audit them, then a simple solution is to press “ctrl+`” (i.e. control key with back tick). This will put the excel sheet in Formula auditing mode and hence all the cells will show the formula rather than the values which will make it easier to audit them. Hope that helps.

Tips about Excel

cksum – compare for multiple files.

Tue, 30 Apr 2013 01:15:30 +0000

If you have to compare cksum for couple of files, the you know how cumbersome it is. So, I wrote a simple script, wherein you can create a file called cksums in the current directory and copy paste the result of “**cksums ***” into this file, and then run this script. Cool 🙂

#!/bin/bash -
#===============================================================================
#
#          FILE: checkcksums.sh
#
#         USAGE: ./checkcksums.sh
#
#   DESCRIPTION: Compare cksums of multiple files.
#
#       OPTIONS: ---
#  REQUIREMENTS: ---
#          BUGS: ---
#         NOTES: ---
#        AUTHOR: Amit Agarwal (),
#  ORGANIZATION:
#       CREATED: 02/22/2013 09:12:17 PM IST
#      REVISION:  ---
#===============================================================================

file=cksums
while read line
do
    a=( $(echo $line) )
    if [[ -f ${a[2]} ]]
    then
        b=( $(cksum ${a[2]}) )
        if [[ $a == $b ]]
        then
            echo "Cksum for ${a[2]} = ${a[0]} matches"
        else
            echo "Failed ::Cksum for ${a[2]} = ${a[0]} matches"
        fi
    else
        echo "Failed :: file ${a[2]} does not exist"
    fi
done < $file

dnsmasq not starting from NetworkManager with SELinux enabled.

Sat, 16 Mar 2013 11:34:11 +0000

OpenWrt – Dnsmasq (Photo credit: magicfab)

Some time back I posted on dnsmasq starting from Network Manager and how to setup dnsmasq.

Now, couple of days back , I setup dnsmasq in NetworkManager but was astonished to see that there was no dnsmasq running. I checked with dig and saw that there was no response from localhost for dns queries. Checked “ps -eaf|grep dns” and found that there was no dnsmasq running. I knew that once you mention “dns=dnsmasq” in the NetworkManager then it should start up but that was not happening. And then I checked audit log, found that some permissions were denied by SELinux.

ssh reverse tunning..

Thu, 14 Feb 2013 00:41:21 +0000

If you want to access some local resources like the release website from the remote server when you are connecting to the remoter server using ssh over VPN, then possibly reverse ssh tunnelling is the best option. So, basically when you are connecting to the remote server, you tell the server your intent to do so and which local resource you want to connect to and on which port.So, here I want to connnet to google.com and tunnel the data to 192.168.131.921:9090 tthough the tunnel, then the command to use will be ::

dnsmasq – use with Network Manager.

Mon, 28 Jan 2013 00:42:24 +0000

Niles Machine Company (Photo credits: roadtrafficsigns.com)

Well if you have not heard about dnsmasq:

Dnsmasq is lightweight, easy to configure DNS forwarder and DHCP server.
It is designed to provide DNS and, optionally, DHCP, to a small network.
It can serve the names of local machines which are not in the global
DNS. The DHCP server integrates with the DNS server and allows machines
with DHCP-allocated addresses to appear in the DNS with names configured
either in each host or in a central configuration file. Dnsmasq supports
static and dynamic DHCP leases and BOOTP for network booting of diskless
machines.

Music players on Linux – the poor mans random song player.

Fri, 20 Jul 2012 06:06:43 +0000

If you have more applications running on your system then your system can handle them then you know what I mean when I say that the Music Players take a lot of CPU. Otherwise harmless, but when you are doing too many things, then lot of times you would feel that probably stopping the Music player might help. But then Linux is all about alternatives. So, there is a command line player called mpg123, which does not use so much CPU. But what about playlist 🙂

Array of all possible colors in bash script

Mon, 07 May 2012 02:17:18 +0000

Sometime back, we had looked at using colors in bash script and here is a way to create a array of all the colors.

#!/bin/bash - 
#===============================================================================
#
#          FILE:  colorarray.sh
# 
#         USAGE:  ./colorarray.sh 
# 
#   DESCRIPTION:  
# 
#       OPTIONS:  ---
#  REQUIREMENTS:  ---
#          BUGS:  ---
#         NOTES:  ---
#        AUTHOR: Amit Agarwal (aka), amit.agarwal@roamware.com
#       COMPANY: Roamware India Pvt Ltd
#       CREATED: 16/04/12 17:24:09 IST
# Last modified: Mon Apr 16, 2012  05:39PM
#      REVISION:  ---
#===============================================================================
count=0
for i in 40m 41m 42m 43m 44m 45m 46m 47m
do
    for l in 0 1
    do
        echo -n "l=$l "
        for k in 0 1
        do
            # echo -n "k=$k "
            for j in {30..37}
            do
                carr[$count]="\033[$k;$j;$l;$i"
                echo -ne "${carr[$count]}$count \033[00m"
                ((count++))
            done
        done
        echo
    done
    echo
done

You can add this script to any script of your choice and you have all the 256 colors available to you in the script without additional coding. Happy coding.

colors in bash scripts

Mon, 30 Apr 2012 03:52:29 +0000

Colours (Photo credit: CherrySoda!)

I have been trying to understand the color codes for bash for a pretty long time, but somehow never got time to understand this clearly. So this time around when I was writing a script to analyze some logs. I thought I will give it a go and finally understood some part of this.

So, first we will start with this script. This is taken from here.

Your own local search engine.

Mon, 09 Apr 2012 02:31:17 +0000

There are times when you would want to have a local search engine capable of indexing even pdf and doc files. So here is a solution.

You can use “Omega” and here are the instructions.

download omega from http:// xapian.org/download

yum install xapian libuuid-devel

And then make and install omega and for this you can follow the instructions.

Federated Search Engine Diagram (Photo credit: Wikipedia)

Create index using command omindex
and then you can use quest or search.py to search or you can setup the cgi way so that you can use local browser to search.

Setup your own RFC Editor for Linux.

Mon, 05 Mar 2012 11:51:54 +0000

Image via Wikipedia

Well, if you are a professional who has to keep referring to RFC, then you know how good it would be to have the RFC downloaded and kept in your computer. But then unless you can search it and use and editor with it, its of not much use. So, here is something that you can do :

Using file partially for filenames

Sun, 12 Feb 2012 06:02:19 +0000

There are some commands that take file name and there are some case where you need to give file name. But there are some cases where you want to modify the file before passing it to the command. What do you do in these case’s?

I had a file containing huge amount of data and for some testing I wanted to pass only the first few lines of the file and not the complete file. And since the file only accepted filename and would not take any input from the STDIN so only option was to create a file with the required data in a temporary file. So, I sat back to figure out some way to do it and finally found I can use this:

Benchmarking the system/CPU performance

Sun, 15 Jan 2012 07:56:44 +0000

Have you ever wanted to have a quick check on your CPU performance. I know that lot of people will say that this is not the right way to do this, but here is something that you can use to check the CPU speed.

#!/bin/bash -
#===============================================================================
#
#          FILE:  benchmark.sh
#
#         USAGE:  ./benchmark.sh
#
#   DESCRIPTION:  Benchmark the CPU
#
#       OPTIONS:  ---
#  REQUIREMENTS:  ---
#          BUGS:  ---
#         NOTES:  ---
#        AUTHOR: Amit Agarwal (aka), amit.agarwal@roamware.com
#       COMPANY: Roamware India Pvt Ltd
#       CREATED: 09/21/2011 11:46:03 AM IST
# Last modified: Wed Sep 21, 2011  12:22PM
#      REVISION:  ---
#===============================================================================

add ()
{
    COUNTER=0
    exec 2>&1
    time=$(exec 2>&1;(time while [[  $COUNTER -lt 100000 ]]; do ((COUNTER++)) \
        ; done))
    echo "Time for 100000 additions is "$time
}	# ----------  end of function add  ----------
mul ()
{
    COUNTER=0
    test=2
    exec 2>&1
    time=$(exec 2>&1;(time while [[  $COUNTER -lt 100000 ]]; do ((COUNTER++)) \
        ; ((test=test*2));done))
    echo "Time for 100000 mul is "$time
}	# ----------  end of function add  ----------
div ()
{
    COUNTER=0
    test=1000000000000
    exec 2>&1
    time=$(exec 2>&1;(time while [[  $COUNTER -lt 100000 ]]; do ((COUNTER++)) \
        ; (( test=test/2)); done)|tr -d '\n')
    echo "Time for 100000 divisions is "${time}
}	# ----------  end of function add  ----------

time add
time mul
time div

And here is the output :

BASH Script Performace

Fri, 06 Jan 2012 06:38:04 +0000

Today we will look at some bash code snippests and the performance issues. Lets first look at the problem and the implemented solution:

Problem: We needed to log the output of the ps command for all the process’s. This was required to be done on per minute basis and the output was required in comma separated files. So, here is what was implemented:

pslog=`ps -e -opid,ppid,user,nlwp,pmem,vsz,rss,s,time,stime,pri,nice,pcp:u,args|grep -v PID|sort -r -k 13,13`
        OLD_IFS=$IFS
        IFS=$'\n'
        logarr=( $pslog )
        for LOGLINE in ${logarr[@]}
        do
                LOGLINE=`echo $LOGLINE|awk '{OFS=",";print $1,$2,$3,$4,$5,$6,$7,:$8,$9,$10,$11,$12,$13,$14}'`
                echo $LOGLINE >> output
        done
        IFS=$OLD_IFS

This was working well and there were no issues. But suddenly we started seeing issues with the reported CPU usages. We would see that whenever this script was running the CPU usage was high, specially if there were too many process’s/thread’s on the system during that time. This code was definitely part of a very large code base, and at this point of time we did not know what was causing the issues.

Rekursive Grep on Solaris or AIX Systems without GNU egrep -r funcionality

Fri, 16 Dec 2011 03:00:27 +0000

If you work regularly on a Solaris or systems which do not have the “-r” (recursive grep) for grep, then you know what a lifesaver this command can be.

Here is one from command line fu:

find . -type f -exec awk '/linux/ { printf "%s %s: %s\n", FILENAME, NR, $0; }' {} \;

The benefit of using awk here is that you can print the line number also 🙂

Backup of files in the directory.

Thu, 01 Dec 2011 11:39:24 +0000

I was working on some scripts and the changes that I was making in the scripts was very dynamic, which I did want to keep backing up in the version control system. But for the peace of my mind, I wanted to keep a copy of the scripts, whenever it was in working state.

Since I had multiple files, so it would make more sense to have a script that could copy all the files in the current directory to “old” directory without over-writing the existing files. So, I wrote a script that would postfix the files with a number. With this approach, finally what I had was the following:

Linux hardware details.

Mon, 28 Nov 2011 11:20:25 +0000

Here is one of the scripts that I found on the net while searching for something … Note the URL for the script in the Description.

#!/bin/bash -
#===============================================================================
#
#          FILE:  linux_hw.sh
#
#         USAGE:  ./linux_hw.sh
#
#   DESCRIPTION:  http://www.howtogeek.com/howto/solaris/get-the-processor-type-on-solaris/
#
#       OPTIONS:  ---
#  REQUIREMENTS:  ---
#          BUGS:  ---
#         NOTES:  ---
#        AUTHOR: Amit Agarwal (aka), amit.agarwal@roamware.com
#       COMPANY: Roamware India Pvt Ltd
#       CREATED: 09/13/2011 03:57:34 PM IST
# Last modified: Sun Oct 30, 2011  04:59PM
#      REVISION:  ---
#===============================================================================

function linux_hw_CPU {
	typeset num=0
	typeset name=""
	typeset cores=""
	name="$( cat /proc/cpuinfo | awk -F: '
/vendor_id/ { vendor=$2 }
/model name/ { model=$2 }
/cpu MHz/ {
if( model ~ "Hz" ) {speed=""} else { speed=$2? MHz" };
print vendor, model, speed; }
		' | tail -1
	)"

        num=$(if [ -r /proc/vmware/cpuinfo ]; then awk '/pcpu/ { print NF-1 }' /proc/vmware/cpuinfo; else cat /proc/cpuinfo | grep processor| wc -l; fi)

	# ESX: mas info sobre logical/cores/packages
	if [ -r /proc/vmware/sched/ncpus ]
	then
		cores=$( echo $( cat /proc/vmware/sched/ncpus ) )
	fi

	echo $num $( echo "$name ($cores)" | enclose )
}

function enclose {
	tr -s " " | sed -e "s/^/\"/; s/$/\"/; s/\"\ /\"/; s/\ \"/\"/"
}

function linux_hw_CPU {

	typeset num=0
	typeset name=""
	typeset cores=""

	name="$(
		cat /proc/cpuinfo | awk -F: '
/vendor_id/ { vendor=$2 }
/model name/ { model=$2 }
/cpu MHz/ {
if( model ~ "Hz" ) {speed=""} else { speed=$2" MHz" };
print vendor, model, speed; }
		' | tail -1
	)"

	num=$(
		if [ -r /proc/vmware/cpuinfo ]
		then
			awk '/pcpu/ { print NF-1 }' /proc/vmware/cpuinfo
		else
			cat /proc/cpuinfo | grep processor| wc -l
		fi

	)

	if grep -q "physical id" /proc/cpuinfo || grep "siblings" /proc/cpuinfo
	then
		chip_count=$( grep "physical id" /proc/cpuinfo | sort -u | wc -l )
		chip_core=$( grep "siblings" /proc/cpuinfo | tail -1 | cut -d: -f2 )
		cores="($chip_count chips x $chip_core cores)"
	fi

	# Blades HP con
	if [ -x /sbin/hpasmcli ]
	then
		chip_name=$( /sbin/hpasmcli -s "SHOW SERVER" | grep "Name" | head -1 | cut -d: -f2 )
		chip_speed=$( /sbin/hpasmcli -s "SHOW SERVER" | grep "Speed" | head -1 | cut -d: -f2 )
		chip_core=$( /sbin/hpasmcli -s "SHOW SERVER" | grep "Core" | head -1 | cut -d: -f2 )
	fi

	# ESX: mas info sobre logical/cores/packages
	if [ -r /proc/vmware/sched/ncpus ]
	then
		cores="($( echo $( cat /proc/vmware/sched/ncpus ) ))"
	fi

	# Linux Itanium IA64
	if grep -q -i itanium /proc/cpuinfo
	then
		name="$(
		grep "vendor" /proc/cpuinfo | cut -d: -f2- | tail -1 ) $(
		grep "arch " /proc/cpuinfo | cut -d: -f2- | tail -1 ) $(
		grep "family" /proc/cpuinfo | cut -d: -f2- | tail -1 ) $(
		grep "cpu MHz" /proc/cpuinfo | cut -d: -f2- | cut -d. -f1 | tail -1 ) Mhz"

		chip_count=$( grep "physical id" /proc/cpuinfo | sort -u | wc -l )
		chip_core=$( grep "siblings" /proc/cpuinfo | tail -1 | cut -d: -f2 )
		cores="($chip_count chips x $chip_core cores)"
	fi

	echo $num $( echo "$name $cores" | enclose )
}

linux_hw_CPU

linux?????? (weijianhui16.wordpress.com)
How to check the uptime of a process (or an application) running in Linux machine using shell script? (singztechmusings.wordpress.com)
Some examples of grep command in unix (javarevisited.wordpress.com)

Add ssh key to remote host

Tue, 15 Nov 2011 08:00:01 +0000

Image via Wikipedia

If you are working on recent versions of the *nix OS like Fedora or Ubuntu then you would know about the commad ssh-copy-id. But if you land up using one of the older versions like Solaris or something where the command is not present, then probably you need a simpler solution to this. One of the simplest solution is with a lot of assumtions, simply copy the id_rsa file to remote server and hope it works. And here is a script to do just that:

Compare files excluding certain lines.

Tue, 18 Oct 2011 11:12:15 +0000

Quick tip, you can use any expression for the sed commands in the (). With this trick you can redirect the stdout of 2 commands to the diff command. This might become very useful, if you want to compare 2 files, excluding the first line.

diff <(sed '1d' file) <(sed '1d' file2)

More interesting example is where the string ABC is converted to abc before comparing in the second file with the following command:

Cont: Get yourself some more conkyrc files.

Wed, 12 Oct 2011 11:03:40 +0000

Last time we got ourselves some conkyrc files from the ubuntu forums. But that scripts gets the files only from the First page of the thread. Lets extend this further and get the script to get all the conkyrc files.

There are some 1048 pages in the thread, I am showing pages 1 to 3 but you can change 3 to whatever number you want 🙂

count=0
for i in {1..3}
do
    >.test
    >conkyrc
	echo "Getting page $i"
	curl http://ubuntuforums.org/showthread.php?t=281865\&page=$i |\\
         sed -n '// d'|\
         sed 's##\n-----------------------------------\n\n\n#' \
         >conkyrc
	dos2unix conkyrc
	cp conkyrc .test
	while [ $(wc -l .test|sed 's/[^0-9]//g') != 0 ]
	do
		sed -n '1,/------------------------/ p' .test|sed '$d' >conkyrc.$count
		diff .test conkyrc.$count |sed 's/^<.//'|sed '1, /---------------------/ d;2d'>.test
		((count++))
	done
	echo "Files so far are : $count"
done

Get yourself some conkyrc files. (amit-agarwal.co.in)
HTC-Like Clock / Weather Conky Configuration (putokaz.wordpress.com)
Split and join file on Mac OSX Terminal (lezeng.wordpress.com)

Script to get yourself some conkyrc files

Sat, 08 Oct 2011 10:37:48 +0000

Continuing from where we left, here is a script that can do all this for you 🙂

curl http://ubuntuforums.org/showthread.php?t=281865\&page=$i | sed -n '/\\/pr/ p'| sed '// d'| sed 's##\n-----------------------------------\n\n\n#' >conkyrc
	dos2unix conkyrc
	cp conkyrc .test
	while [ $(wc -l .test|sed 's/[^0-9]//g') != 0 ]
	do
		sed -n '1,/------------------------/ p' .test|sed '$d' >conkyrc.$count
		diff .test conkyrc.$count |sed 's/^<.//'|sed '1, /---------------------/ d;2d'>.test
		((count++))
	done

This will create couple of conkyrc.files in the current directory. Each of these is one from the web-page that I mentioned earlier. So, enjoy….

Creating a chroot environment – the script.

Fri, 23 Sep 2011 09:47:48 +0000

Here is the script, very simple and effective 🙂

#!/bin/bash -
#===============================================================================
#
#          FILE:  mkchroot.sh
#
#         USAGE:  ./mkchroot.sh
#
#   DESCRIPTION:  Make a  chroot environ and cd to it
#
#       OPTIONS:  ---
#  REQUIREMENTS:  ---
#          BUGS:  ---
#         NOTES:  ---
#        AUTHOR: Amit Agarwal (aka), 
#       CREATED: 09/03/2011 02:53:37 PM IST
# Last modified: Sat Sep 03, 2011  03:11PM
#      REVISION:  ---
#===============================================================================

 binaries=( bash2 ls cat vi vim sudo)
#===  FUNCTION  ================================================================
#          NAME:  copy_binary
#   DESCRIPTION:  copy binary to chroot
#    PARAMETERS:
#       RETURNS:
#===============================================================================

copy_binary ()
{
   cmd=`which $1`
   echo $cmd
   cp $cmd bin/
   ldd $cmd
   while read line
   do
      while read ld
      do
         if [[ -f $ld ]]
         then
            echo copy $ld
            cp $ld lib/
            if [[ -L $ld ]]
            then
               ld1=$( ls -l $ld |sed 's/.*> //')
               echo "  copy $ld1"
               cp  /lib/$ld1 lib/
            fi
         fi
      done < <(echo $line|sed 's/.*> //'|sed 's/ .*//')
   done < <(ldd $cmd)
}	# ----------  end of function copy_binary  ----------

#===  FUNCTION  ================================================================
#          NAME:  init
#   DESCRIPTION:  Do the required initialization
#    PARAMETERS:
#       RETURNS:
#===============================================================================
init()
{
   mkdir -p {root,home,dev,etc,lib,usr,bin}
   mkdir -p usr/bin
   mkdir -p libexec/openssh



   mknod -m 666 dev/null c 1 3

   cd etc
   cp /etc/ld.so.cache .
   cp -avr /etc/ld.so.cache.d/ .
   cp -avr /etc/ld.so.conf.d/ .
   cp /etc/ld.so.conf .
   cp /etc/nsswitch.conf .
   cp /etc/passwd .
   cp /etc/group .
   cp /etc/hosts .
   cp /etc/resolv.conf .
   cd -
}
cd $1
if [[ -f .status ]]
then
   cat .status
   echo "Not running now"
else
   init
   for i in ${binaries[*]}
   do
       copy_binary $i
       cp -avr /etc/${i}* etc/
   done
   ln bin/bash2 bin/bash
   echo "complete" > .status
fi
cp -avr ~/bin/automation root/automation
sudo chroot .

Creating a chroot environment in Fedora with bash and other utils.

Mon, 19 Sep 2011 14:59:23 +0000

[ad#ad-2]

I am testing some of my scripts to work on a very old system and there the versions of the most popular applications are very old, real old :(. So, some of things that I am very used to since last couple of years, do not seem to work as expected and I need to keep verifying a lot of things on the server, very inconvinient to keep testing the script on the server (need to connect on VPN) just to test some very simple things.

faster bash operations on files with File Descriptors.

Sat, 11 Jun 2011 02:11:53 +0000

I was writing a bash script that would do some operations and read and write to file. Seems that that was pretty simple with

  <td>
    <div class="text codecolorer">
      while read line<br /> <br /> do<br /> <br /> done<file
    </div>
  </td>
</tr>

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and then use redirection operations like “>” and “»” to write to file. Done with the script pretty fast. So far so good, when I went for real life tests, no one was interested in using it, why? Simple, it was simply taking too long. The file was reading about 10K lines and writing about 50 lines and was taking about more than 10 minutes.

Terminating a SSH session after starting background process.

Sat, 14 May 2011 16:59:43 +0000

This is too good. If you are planning to start a background process in the bash script in the background and continue in the script, you cannot do it until…….

You would need to close the stdout/stdin and stderr before you can terminate any ssh session automatically. Here’s some more light on this topic.

http://lists.debian.org/debian-user/2005/09/msg00254.html

On Thu, Sep 01, 2005 at 05:33:28PM -0400, Roberto C. Sanchez wrote: > I occasionally log into a machine remotely and start a process in the > background: > > command & > > However, when I log out of the machine, the ssh process on my local > machine blocks. I guess that it is becuase the remote still has jobs > running. Is there a way to get it start the process in the background > and then detach from the shell? I have already tried this:

browsing the windows machines and their shares – listing

Sat, 30 Apr 2011 15:01:55 +0000

smbtree is a very nice command to check all the machines that are present in the LAN (your connected network). For this to work you may need to look at this article also.

  <td>
    <div class="text codecolorer">
      smbtree -U <strong>username
    </div>
  </td>
</tr>

Prompted for a username and password when browsing to an IIS virtual directory (ask.metafilter.com)
How to Delete History in Internet Explorer (lockergnome.com)
How To Guide: Deploy VNC via Group Policy (edugeek.net)
Windows just doesn’t like tunnels (ask.metafilter.com)
Windows Tips – Speed Up your Network Share Browsing (hitechbarkadaz.wordpress.com)

client lanman auth is disabled error for samba

Thu, 28 Apr 2011 14:58:30 +0000

The error:

Server requested LANMAN password (share-level security) but ‘client lanman auth’ is disabled

is easily fixable. You just need to tell samba that client lanman auth is enabled. And here is how to do this:

If you are getting this error then add the following in the globals section of the samba configuration:

client lanman auth = Yes

Ensure that you change this in the file /etc/samba/smb.conf

10 Useful Sar (Sysstat) Examples for UNIX / Linux Performance Monitoring

Fri, 22 Apr 2011 02:20:48 +0000

10 Useful Sar (Sysstat) Examples for UNIX / Linux Performance Monitoring

by Ramesh Natarajan on March 29, 2011

Using sar you can monitor performance of various Linux subsystems (CPU, Memory, I/O..) in real time.

Using sar, you can also collect all performance data on an on-going basis, store them, and do historical analysis to identify bottlenecks.

Sar is part of the sysstat package.

This article explains how to install and configure sysstat package (which contains sar utility) and explains how to monitor the following Linux performance statistics using sar.

The Ultimate Guide to Getting Support on Linux-use empathy to login to IRC….

Mon, 18 Apr 2011 12:14:49 +0000

The Ultimate Guide to Getting Support on Linux
Installing Linux has become effortless to the extent that anyone with a little knowledge of computers can get a Linux machine up and running instantly. However, many of them throw in the towel when faced with even the slightest of glitches. The main reason for this is the belief that Linux doesn’t offer any kind of support.

Other problem users face is that the regular technician who repairs their computer refuses even to touch a machine that’s running Linux. So, if you are one of those users disgruntled after encountering a multitude of problems with a fresh Linux install — don’t panic and read on to know some ways in which you could get support for your Linux installation.

vim autocomplete – automagically without tab.

Sat, 16 Apr 2011 01:10:59 +0000

Lets first do the setup in one line. Get my vim script downloader.

Use the script to add the script with script ID : :1879 (vim-autocomplpop) to your list of plugins for vim and you are done.

If you are using snipmate, then make sure that you read the description of the plugin to add the required lines to the vimrc file to get the full functionality. You would love to type henceforth in your favourite editor. We will talk about more on Intellisense in few days time.. Chao till then.

Easy ssh configuration with .ssh/config file

Mon, 11 Apr 2011 06:30:00 +0000

If you ssh to many hosts then you are aware of the pain that it takes to ssh with different username and hostname. There is an alias that you can creat with native ssh though. Here I will show you the same with an example.

  <td>
    <div class="text codecolorer">
      cat <<EOF >>~/.ssh/config<br /> Host <alias><br /> Username <user name><br /> Port <port number><br /> Hostname <hostname>
    </div>
  </td>
</tr>

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You can optionally omit the parameters that you do not require explicitly. For example, if your port number is default then you can simply ignore the parameter.

Try all colors in xterm with script before setting the color

Fri, 18 Mar 2011 07:41:39 +0000

If you are looking for testing the colors on how they would look like in the xterm before you set the color then here is a small script for you.

  <td>
    <div class="text codecolorer">
      #!/bin/bash -<br /> #===============================================================================<br /> #<br /> #          FILE:  xterm_colors-test.sh<br /> #<br /> #         USAGE:  ./xterm_colors-test.sh<br /> #<br /> #   DESCRIPTION:  Test all the colors for xterm bg<br /> #<br /> #       OPTIONS:  ---<br /> #  REQUIREMENTS:  ---<br /> #          BUGS:  ---<br /> #         NOTES:  ---<br /> #        AUTHOR:   Amit Agarwal (amit.agarwal@amit-agarwal.co.in), aka<br /> #       COMPANY:  Individual<br /> #       VERSION:  1.0<br /> #       CREATED:  02/18/2011 01:02:51 PM IST<br /> #      REVISION:  1.0<br /> #===============================================================================<br /> <br /> cat /usr/share/X11/rgb.txt |sed 's/\([0-9]\{1,3\}[ \t]*\)\{3\}//'|sed 's/^ *//' >~/rgb.txt<br /> while read line<br /> do<br /> bg=$(echo $line)<br /> echo $line<br /> echo "Trying $bg color"<br /> xterm -bg "$bg"&<br /> sleep 5<br /> kill -9 $!<br /> done < ~/rgb.txt
    </div>
  </td>
</tr>

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This can be used in various ways but I will leave the choice to you. One option that I should probably still tell is :

what is vim in 6Kb..

Wed, 16 Mar 2011 16:36:33 +0000

If you thought that vim is very bloated and nothing abuot this editor can be small, then you are not alone. I was myself in the same bandwagon.

Well, I never thought that there could be anything about vim that can be explained in Kb’s, lest alone the complete vim features. But looks like vim.org had thought about this and thus came up with this. And here is the direct link to the vim in 6kb in English.

All in one solution for all the scripts of vim from vim.org

Wed, 09 Mar 2011 16:39:52 +0000

For quite sometime now, I was looking for some console based program which would help me get the scripts from vim.org. A simple solution would have been to do a wget for the scripts. But since there are so many scripts coming up daily and with a need to search based on script ID and name of the script, I thought better to write a script that can do all of those things. Now, what was required was that the script should be either able to download this or add to the GLVS script. Also note that, I had done something similar in the past here. There are some additions in the below script. You can download a copy of the script get_vim_scripts. Or you can copy the script from below:

using gnuplot for time plotting

Thu, 17 Feb 2011 15:11:40 +0000

Couple of days back, I was working with some data and wanted to plot it. I had couple of options Excel, ploticus and then our own gnuplot. My choice here was gnuplot, as this is most commonly available and helps me write scripts that can automate my repetitive task. So far, so good. The data I was plotting was against time, that was the problem. Couple of quick searches did not result into any luck to get me on the path and hence with some man pages and some documentation, finally I found this, might be this will be helpful for others.

bash mathematical calculators.

Tue, 25 Jan 2011 21:46:34 +0000

To start with , the most simple and easy to use should be “bc”. but just for some guys who want to be more experimental, here are few more bash calulator programs. These are completely command line and thus you can completely integrate them in your shell script or use them in shell script to do some really crazy maths calculations.

  <td>
    <div class="text codecolorer">
      sudo yum install calc clac
    </div>
  </td>
</tr>

Lets start with installing these. Before we start, don’t blame and flame me if your favourite is not there in the list. If it is not, better is you drop me a comment or email, and I will see, if I can include it in the list above, but remember this is only for console based calculators.

Find all the missing paths in the PATH variable in bash script

Thu, 20 Jan 2011 02:36:00 +0000

Here is a simple script that will list out all the paths in the PATH variable that do not exist.

  <td>
    <div class="text codecolorer">
      #!/bin/bash -<br /> #===============================================================================<br /> #<br /> #          FILE:  wrong_path.sh<br /> #<br /> #         USAGE:  ./wrong_path.sh<br /> #<br /> #   DESCRIPTION:  Show Directories in the PATH Which does NOT Exist<br /> #<br /> #       OPTIONS:  ---<br /> #  REQUIREMENTS:  ---<br /> #          BUGS:  ---<br /> #         NOTES:  ---<br /> #        AUTHOR:  Amit Agarwal (AKA), amit.agarwal@amit-agarwal.co.in<br /> #       COMPANY:  Individual<br /> #       VERSION:  1.0<br /> #       CREATED:  09/20/2009 09:15:48 AM IST<br /> #      REVISION:  ---<br /> #===============================================================================<br /> <br /> set -o nounset                              # Treat unset variables as an error<br /> <br /> (IFS=:;for p in $PATH; do test -d $p || echo $p; done)
    </div>
  </td>
</tr>

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New feature in Nautilus – resize icon on desktop.

Mon, 10 Jan 2011 15:36:25 +0000

On Desktop on Gnome using nautilus, now you can resize individual icons. Just right click on the icon to resize and in the menu you will get a resize icon :

[][1]

Resize icon

and then you can resize the icon from the borders:

[][2]

Resize icon

“Where is this icon?” Nautilus script is incredibly nifty (omgubuntu.co.uk)
Use Nautilus’ Emblems feature to keep your home folder organised (omgubuntu.co.uk)
Screenshots: Desktop Unity in Natty (omgubuntu.co.uk)
Add a quick-access shortcuts to the GNOME right-click menu (ghacks.net)

Shell Scripting

Wed, 05 Jan 2011 15:08:44 +0000

Here are some links for bash programming that you may find useful.

http://tips-linux.net/en/content/pro-bash-programming

http://tips-linux.net/en/content/expert-shell-scripting

http://tips-linux.net/en/content/beginning-linux-command-line

http://tips-linux.net/en/content/bash-pocket-reference

http://tips-linux.net/en/content/linux-command-line-and-shell-scripting-bible

Linux – Learning the Shell (edugeek.net)
10 Useful Tools, Websites And Tricks to Help You Master Linux Command (maketecheasier.com)
lf-submit.sh – Bash mplayer Last.fm scrobbler (yjl.im)
Linux command line tricks you need to know: IO redirection and piping (interstellr.com)
imabonehead: Houcem HACHICHA’s Blog: My top ten shell/bash tricks! (houcemhachicha.blogspot.com)

Execute a command with a timeout

Wed, 29 Dec 2010 15:03:18 +0000

Execute a command with a timeout

  <td>
    <div class="text codecolorer">
      &nbsp;timelimit -t100 somecommand
    </div>
  </td>
</tr>

I found this in Ubuntu repos, and consider it better than timeout.

* View this command to comment, vote or add to favourites * View all commands by CodSpirit

write the output of a command to /var/log/user.log… each line will contain $USER, making this easy to grep for.

Tue, 28 Dec 2010 15:00:24 +0000

write the output of a command to /var/log/user.log… each line will contain $USER, making this easy to grep for.

  <td>
    <div class="text codecolorer">
      &nbsp;log() { (echo "$ $@";$@) | logger -t $USER; }
    </div>
  </td>
</tr>

This command is useful if you want to copy the output of a series of commands to a file, for example if you want to pastebin the output from ‘uname -a’, ‘lspci -vvv’ and ‘lsmod’ for video driver trouble-shooting on your favorite Linux forum.

Empty a file

Sun, 26 Dec 2010 14:56:13 +0000

This one is for those who know the “touch” command. Hope all of us do not follow a command just because it is on one of the popular site without trying to understand the command and the output.

Bash Script Beautifier

Thu, 23 Dec 2010 14:51:01 +0000

Today I was working on a bash script written by someone else. And the script was maintained since long and had actually become quite big and there was no indentation followed. So, you can understand how difficult it was to understand the script. So, I set my foot forth to first find a beautifier for the bash script before I fixed it and my search ended here.

Take a screenshot of the window the user clicks on and name the file the same as the window title

Sun, 19 Dec 2010 14:45:06 +0000

Take a screenshot of the window the user clicks on and name the file the same as the window title

  <td>
    <div class="text codecolorer">
      &nbsp;sleep 4; xwd >foo.xwd; mv foo.xwd "$(dd skip=100 if=foo.xwd bs=1 count=256 2>/dev/null | egrep -ao '^[[:print:]]+' | tr / :).xwd"
    </div>
  </td>
</tr>

In general, this is actually not better than the “scrot -d4” command I’m listing it as an alternative to, so please don’t vote it down for that. I’m adding this command because xwd (X window dumper) comes with X11, so it is already installed on your machine, whereas scrot probably is not. I’ve found xwd handy on boxen that I don’t want to (or am not allowed to) install packages on.

Repeat a portrait eight times so it can be cut out from a 6″x4″ photo and used for visa or passport photos

Fri, 17 Dec 2010 14:41:57 +0000

Repeat a portrait eight times so it can be cut out from a 6″x4″ photo and used for visa or passport photos

  <td>
    <div class="text codecolorer">
      montage 2007-08-25-3685.jpg +clone -clone 0-1 -clone 0-3 -geometry 500 -frame 5 output.jpg
    </div>
  </td>
</tr>

Yes, You could do it in the GIMP or even use Inkscape to auto-align the clones, but the command line is so much easier.

Screen enable/disable logging in all windows

Fri, 19 Nov 2010 15:13:30 +0000

If you use screen command a lot then this is something that you will like 🙂

Screen enable/disable loggin in all windows

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    <div class="text codecolorer">
      bindkey ^l at "#" log on<br /> <br /> bindkey ^o at "#" log off
    </div>
  </td>
</tr>

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The command when added in screenrc enables logging all open windows by using the C-l (control-l key combination) and disable by C-o . The lines need to be added in separate lines .

OpenLDAP and SSL – some links

Mon, 15 Nov 2010 14:51:49 +0000

Here are some of the links that may be of great help to you if you are having issues with setting up SSL and OpenLDAP. I was having some issues with this setup and these links helped me fix the same.

http://www.faqs.org/docs/Linux-HOWTO/SSL-RedHat-HOWTO.html

http://www.tc.umn.edu/~brams006/selfsign_redhat.html

http://docs.redhat.com/docs/en-US/Red_Hat_Directory_Server/8.1/html/Using_Red_Hat_Console/Starting_the_Server_with_SSL_Enabled-Enabling_SSL_in_the_DS_Admin_Server_and_Console.html

http://directory.fedoraproject.org/wiki/Howto:SSL http://www.linuxtopia.org/online_books//network_administration_guides/ldap_administration/appendix-common-errors_Common_causes_of_LDAP_errors.html

Stephan Hermann: Ubuntu 10.04 LTS and OpenLDAP (shermann.name)
Exploring LDAP SASL Authentication With Ruby (intridea.com)
Stephan Hermann: [SOLVED] OpenLDAP, passwd and CRYPT passwords (shermann.name)
Moodle – Slow LDAP Login (edugeek.net)

Firesheep addon allows the clueless to hack Facebook, Twitter over Wi-Fi

Sat, 13 Nov 2010 03:51:20 +0000

Firesheep addon allows the clueless to hack Facebook, Twitter over Wi-Fi If you thought hijacking a user’s social media session was only done by skilled hackers, now the Firesheep addon can allow even the truly clueless to become an Internet griefer.

URL: http://feeds.digg.com/~r/digg/topic/linux_unix/popular/~3/cb0qD08tfpU/firesheep_addon_allows_the_clueless_to_hack_facebook_twitter_over_wi_fi

Firesheep – a new tool for capturing data on unsecured WiFi (voipsa.org)
Firesheep: Why You May Never Want to Use an Open Wi-Fi Network Again (blogs.forbes.com)
Firesheep session hijacking tool makes public Wi-Fi useless (gizmag.com)
Firefox Add-on Firesheep Brings Hacking to the Masses (pcworld.com)

Quick tip on zipping logs in real time.

Wed, 13 Oct 2010 17:57:53 +0000

Sometimes, some small things that we don’t actually think can be useful are such useful. I faced this couple of days back when I was working on something and the amount of logs getting generated and the files getting rotated was too fast. If I had to use this for sometime, I needed some script, application or something to make sure that the logs are zipped every few seconds. Finding an application for this would take time and what good is bash if we need to find applications for this. So, a simple bash command did the trick. Most of us would know this but applying it and using it at the right time, was what saved my life. Thanks to bash. Here is the command:

Introduction to the Command Line (Second Edition) — Free Ebook Download

Wed, 06 Oct 2010 15:21:46 +0000

Pretty good book for beginners on command line whether you work on Ubuntu, Fedora, BSD or any other version.

http://www.lulu.com/product/ebook/introduction-to-the-command-line-%28second-edition%29/12665426

Install LibreOffice on Fedora and Ubuntu (ghacks.net)
Learn To Use The Ubuntu Command Line With CLIcompanion (makeuseof.com)
How To Install GIMP in Ubuntu (crenk.com)

[Solved] Abbreviations not working in vim

Sat, 02 Oct 2010 15:17:39 +0000

Today I found that abbreviations are not working in vim in my current login. I searched log of blog’s and sill did not find any solution so I decided to take the matters in my hand.

To start with I disabled all the plugin’s by moving my plugin directory. This did not help me solve the issue, so the only other option left was to now disable the vimrc file completely. Once I removed the vimrc file, the abbreviations started working.

bash script to run a command and take screenshot in every loop.

Fri, 24 Sep 2010 16:02:14 +0000

Couple of days back, I had posted a command to display a stop timer with bash and echo. There I had also put the following gif file:

Here the tricky part was to capture the jpg’s to create the gif file.

Preparation:

Rename the terminal to aka – amit-capture

Execute the command once with the import command and check the output and jpg’s

bash – echo command with option to display the output on the same line.

Tue, 21 Sep 2010 15:15:05 +0000

Here is a nice little trick to display the output in the same line :

  <td>
    <div class="bash codecolorer">
      &nbsp;<span class="kw3">echo</span> <span class="re5">-ne</span> <span class="st0">"output\<span class="es1">\r</span>"</span>
    </div>
  </td>
</tr>

The trick here is simple, first we disable the <a class="zem_slink" title="Newline" rel="wikipedia" href="http://en.wikipedia.org/wiki/Newline">newline printed by <a class="zem_slink" title="Echo (command)" rel="wikipedia" href="http://en.wikipedia.org/wiki/Echo_%28command%29">echo command with the ”-n” option and then we enable the interpretation of the <a class="zem_slink" title="Backslash" rel="wikipedia" href="http://en.wikipedia.org/wiki/Backslash">backslash characters with the ”-e” option. As the ”\r” is used as <a class="zem_slink" title="Carriage return" rel="wikipedia" href="http://en.wikipedia.org/wiki/Carriage_return">carriage return which brings you to the start of the line without the newline (like in <a class="zem_slink" title="Typewriter" rel="wikipedia" href="http://en.wikipedia.org/wiki/Typewriter">typewriter), we will use the same to get the desired effect. So, if you wanted a stopwatch for a 100 seconds on the console then this simple bash <a class="zem_slink" title="For loop" rel="wikipedia" href="http://en.wikipedia.org/wiki/For_loop">for loop would do the same:

OpenID for non-SuperUsers

Tue, 07 Sep 2010 23:36:05 +0000

Based on the results of my Unobtrusive <a class="zem_slink" title="OpenID Foundation" rel="homepage" href="http://openid.net">OpenID post, it is quite evident that there is a lot of partial <a class="zem_slink" title="Knowledge" rel="wikipedia" href="http://en.wikipedia.org/wiki/Knowledge">knowledge about OpenID out there. While my knowledge on the subject is far from complete, this post is my attempt to share what I have learned with others.

The target audience for the bulk of this post is people who are capable of adding autodiscovery links to their blog templates, may be able to install a small <a class="zem_slink" title="PHP" rel="homepage" href="http://www.php.net/">PHP script and/or know what a <a class="zem_slink" title="Hypertext Transfer Protocol" rel="wikipedia" href="http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol">HTTP <a class="zem_slink" title="List of HTTP headers" rel="wikipedia" href="http://en.wikipedia.org/wiki/List_of_HTTP_headers">header is.

Getting your wordpress self hosted stats on your console with bash script.

Tue, 29 Jun 2010 12:23:05 +0000

Some time back I wrote a blog on how to get your site stats using curl in <a class="zem_slink freebase/en/bash" title="Bash" rel="homepage" href="http://tiswww.case.edu/php/chet/bash/bashtop.html">bash shell. Today we will use the same script to get the stats every few seconds on the terminal on the same line, similar to progress meter.

Here is the script and the description:

  <td>
    <div class="bash codecolorer">
      <span class="co0">#!/bin/bash -</span><br /> <span class="co0">#===============================================================================</span><br /> <span class="co0">#</span><br /> <span class="co0">#          FILE:  update_stats.sh</span><br /> <span class="co0">#</span><br /> <span class="co0">#         USAGE:  ./update_stats.sh</span><br /> <span class="co0">#</span><br /> <span class="co0">#   DESCRIPTION:  Update the stats inline in shell every $1 seconds.</span><br /> <span class="co0">#</span><br /> <span class="co0">#       OPTIONS:  ---</span><br /> <span class="co0">#  REQUIREMENTS:  ---</span><br /> <span class="co0">#          BUGS:  ---</span><br /> <span class="co0">#         NOTES:  ---</span><br /> <span class="co0">#        AUTHOR:  <a class="zem_slink" title="Amit Agarwal" rel="homepage" href="http://amit-agarwal.co.in">Amit Agarwal</a> (AKA), amit.agarwal@amit-agarwal.co.in</span><br /> <span class="co0">#       COMPANY:  Individual</span><br /> <span class="co0">#       VERSION:  1.0</span><br /> <span class="co0">#       CREATED:  06/21/2010 11:27:16 PM IST</span><br /> <span class="co0">#      REVISION:  ---</span><br /> <span class="co0">#===============================================================================</span><br /> <br /> <span class="re2">sleep_time</span>=<span class="nu0">30</span> <span class="co0">#the time to wait between stats collection</span><br /> <span class="re2">run_stats</span>=get_stats  <span class="co0"># the script to run to get the stats</span><br /> <span class="re2">filename</span>=<span class="sy0">/</span>tmp<span class="sy0">/</span>statpress.html <span class="co0"># the filename where the script is storing the html file of your statpress page.</span><br /> <span class="kw3">eval</span> <span class="re1">$run_stats</span> <span class="nu0">2</span><span class="sy0">><</span>a <span class="re2">class</span>=<span class="st0">"zem_slink freebase/en/dev_null"</span> <span class="re2">title</span>=<span class="st0">"/dev/null"</span> <span class="re2">rel</span>=<span class="st0">"wikipedia"</span> <span class="re2">href</span>=<span class="st0">"http://en.wikipedia.org/wiki//dev/null"</span><span class="sy0">>/</span>dev<span class="sy0">/</span>null<span class="sy0"></</span>a<span class="sy0">></span><br /> <span class="kw1">while</span> <span class="br0">&#40;</span><span class="kw2">true</span><span class="br0">&#41;</span><br /> <span class="kw1">do</span><br /> <span class="sy0"><!</span>--loginview start--<span class="sy0">></span><span class="re2">values</span>=$<span class="br0">&#40;</span><span class="kw2">cat</span> <span class="re1">$filename</span> <span class="sy0">|</span> w3m <span class="re5">-dump</span> <span class="re5">-T</span> <span class="sy0"><</span>a <span class="re2">class</span>=<span class="st0">"zem_slink freebase/en/html"</span> <span class="re2">title</span>=<span class="st0">"HTML"</span> <span class="re2">rel</span>=<span class="st0">"wikipedia"</span> <span class="re2">href</span>=<span class="st0">"http://en.wikipedia.org/wiki/HTML"</span><span class="sy0">></span>text<span class="sy0">/</span>html<span class="sy0"></</span>a<span class="sy0">></span> <span class="sy0">|<</span>a <span class="re2">class</span>=<span class="st0">"zem_slink freebase/en/grep"</span> <span class="re2">title</span>=<span class="st0">"Grep"</span> <span class="re2">rel</span>=<span class="st0">"wikipedia"</span> <span class="re2">href</span>=<span class="st0">"http://en.wikipedia.org/wiki/Grep"</span><span class="sy0">></span><span class="kw2">grep</span><span class="sy0"></</span>a<span class="sy0">></span> <span class="st0">"^Visitor\\|^Pageviews"</span><span class="sy0">|<</span>a <span class="re2">class</span>=<span class="st0">"zem_slink freebase/en/awk"</span> <span class="re2">title</span>=<span class="st0">"AWK"</span> <span class="re2">rel</span>=<span class="st0">"homepage"</span> <span class="re2">href</span>=<span class="st0">"http://cm.bell-labs.com/cm/cs/awkbook/index.html"</span><span class="sy0">></span><span class="kw2">awk</span><span class="sy0"></</span>a<span class="sy0">></span> <span class="co3">\'</span><span class="br0">&#123;</span>print <span class="re4">$1</span><span class="nu0"></span><span class="br0">&#125;</span><span class="co3">\'</span><span class="sy0">|</span><span class="kw2">tr</span>  <span class="st0">"\<span class="es1">\n</span>"</span> <span class="st0">" "</span><span class="br0">&#41;</span><br /> <span class="re2">time</span>=$<span class="br0">&#40;</span><span class="kw2">date</span><span class="br0">&#41;</span><br /> <span class="kw3">printf</span> <span class="st0">"<span class="es2">$time</span> --> <span class="es2">$values</span> \<span class="es1">\r</span>"</span><span class="sy0"><!</span>--loginview end--<span class="sy0">></span><br /> <span class="kw2">sleep</span> <span class="re1">$sleep_time</span><br /> <span class="kw1">done</span>
    </div>
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for loop in bash script on solaris without seq (amit-agarwal.co.in)
Get the mappings from tex file for vim plugins (amit-agarwal.co.in)
unbound variable – bash completion not working and having issues with other stuff like command not found. (amit-agarwal.co.in)
bash builtins (almirkaric.com)

bash one liner to change/remove test pattern from config file or text file.

Fri, 25 Jun 2010 11:47:05 +0000

Problem:

I had a directory with a lot of config files in the ini file format, i.e. name and value separated by equals. Some/all of these contained some directory names and other values which had to be replaced. But there were other place where I should not not replace them, if there was no exact match. I also needed to have a backup copy of the file that I was modifying. Since the number of files that I needed to change was multiple so was quite difficult to do it without using some script.

find duplicate entry in a list in bash with sed

Fri, 25 Jun 2010 11:46:58 +0000

Here I will take an example of rss2email list, but I guess I will be able to pass on the concept.

Here is example of the output of the r2e list command:

1: http://blog.amit-agarwal.co.in/feed (default: amitag@localhost)
2: http://feeds2.feedburner.com/AllAboutLinux (default: amitag@localhost)
3: http://feeds2.feedburner.com/Command-line-fu (default: amitag@localhost)
4: http://blogs.members.freewebs.com/Members/Blogs/viewBlogRSS.jsp?userid=29731143 (default: amitag@localhost)

Target here is to get the list of all duplicate entries if any. So, first we need to remove the numbers from the begining and the email ID from the end.

bash script to change the vim colorscheme from the list of locally available schemes

Thu, 24 Jun 2010 20:51:35 +0000

: Image via Wikipedia

Today I was just wondering how good it would be to have a script to change the <a class="zem_slink freebase/en/vim" title="Vim (text editor)" rel="homepage" href="http://www.vim.org/">vim colorscheme from the <a class="zem_slink freebase/en/cmd_exe" title="Command Prompt" rel="wikipedia" href="http://en.wikipedia.org/wiki/Command_Prompt">command prompt. The plan for the script was simply to print the list of available schemes and then let the user select the actions from there on. So, here is the result:

cdargs – bash cd command with bookmarks and browser.

Tue, 22 Jun 2010 02:37:47 +0000

: Image via Wikipedia

cdargs is a <a class="zem_slink freebase/en/bash" title="Bash" rel="homepage" href="http://tiswww.case.edu/php/chet/bash/bashtop.html">bash shell cd with bookmarks and browser. Quite useful if you are developer or someone who use’s the bash shell very frequently

Name       : cdargs

Arch : i686 Version : 1.35 Release : 5.fc12 Size : 114 k Repo : installed From repo : fedora Summary : The shell cd with bookmarks and browser URL : http://www.skamphausen.de/software/cdargs/ License : <a class="zem_slink freebase/en/gnu_general_public_license" title="GNU General Public License" rel="wikipedia" href="http://en.wikipedia.org/wiki/GNU_General_Public_License">GPLv2</a>+ Description: Enables the user to quickly change <a class="zem_slink freebase/en/working_directory" title="Working directory" rel="wikipedia" href="http://en.wikipedia.org/wiki/Working_directory">working directory</a> by navigating cd arguments : and expanding the shell built-in cd with bookmarks and browser.

List of commands you use most often

Wed, 16 Jun 2010 02:17:01 +0000

<span style="font-size: x-large;"><a href="http://feedproxy.google.com/~r/Command-line-fu/~3/6MxHiSiINdo/list-of-commands-you-use-most-often">List of commands you use most often

$ history | <a class="zem_slink freebase/en/awk" title="AWK" rel="homepage" href="http://cm.bell-labs.com/cm/cs/awkbook/index.html">awk '{a[$2]++}END{for(i in a){print a[i] " " i}}' | sort -rn | head > /tmp/cmds | gnuplot -persist <(echo 'plot "/tmp/cmds" using 1:xticlabels(2) with boxes') Plot your most used commands with gnuplot.

<a href="http://www.commandlinefu.com/commands/view/5845/list-of-commands-you-use-most-often">View this command to comment, vote or add to favourites
<a href="http://feeds2.feedburner.com/commands/by/sthrs">View all commands by <a href="http://feeds2.feedburner.com/commands/by/sthrs">sthrs

Verify all the paths in the PATH directory

Tue, 08 Jun 2010 09:13:35 +0000

Here is the command to test that all the directories in your path actually exist.

(<a class="zem_slink freebase/en/internal_field_separator" title="Internal field separator" rel="wikipedia" href="http://en.wikipedia.org/wiki/Internal_field_separator">IFS=:;for p in $PATH; do test -d $p || echo $p; done)

And the explanation :

Set the IFS to ”:”

now we loop through the PATH variable

and test all the directories with ”test -d”

Here is another version without IFS:

for i in ${PATH//:/ };do test -d $i || echo $i;done

PuTTY alternatives - AlternativeTo.net

Fri, 04 Jun 2010 02:06:45 +0000

Sometimes after hours of searching you find a link so good that it needs no introductions and neither any writeup. I found one such page today :

<a href="http://alternativeto.net/desktop/putty/">http://alternativeto.net/desktop/putty/<h6 class="zemanta-related-title">Related articles by Zemanta <ul class="zemanta-article-ul"> <li class="zemanta-article-ul-li"><a href="http://www.downloadsquad.com/2010/05/18/kitty-is-win32-native-putty/">KiTTY is Win32-native PuTTY (downloadsquad.com) <li class="zemanta-article-ul-li"><a href="http://blog.amit-agarwal.co.in/2010/04/11/putty-export-client-display-on-login-for-opening-x-application-and-terminal/">PuTTY export client display on login for opening X application and terminal. (amit-agarwal.co.in) <li class="zemanta-article-ul-li"><a href="http://colonelqubit.wordpress.com/2010/05/05/time-to-empty-my-pockets-for-foss-projects/">Time to empty my pockets for FOSS projects (colonelqubit.wordpress.com) <div class="zemanta-pixie"><a class="zemanta-pixie-a" title="Reblog this post [with Zemanta]" href="http://reblog.zemanta.com/zemified/a0e0301f-eb88-41fd-afbb-ab5bea19c81b/"><img class="zemanta-pixie-img" src="http://blog.amit-agarwal.co.in/wp-content/uploads/2010/08/reblog_b96.png" alt="Reblog this post [with Zemanta]" /><span class="zem-script more-related more-info pretty-attribution paragraph-reblog">

vim – get the list of all the scripts available.

Thu, 27 May 2010 20:26:35 +0000

To get a list of all the scripts in the vim.sf.net project, you can run the following command. This will list all the scripts with the script id.

wget -O – ’http://www.vim.org/scripts/script_search_results.php?&show_me=4000&result_ptr=0’ -o /dev/null | <a class="zem_slink freebase/en/grep" title="Grep" rel="wikipedia" href="http://en.wikipedia.org/wiki/Grep">grep width| grep script_id= |<a class="zem_slink freebase/en/sed" title="Sed" rel="wikipedia" href="http://en.wikipedia.org/wiki/Sed">sed ’s/.*script_id=//’|tr -d ”””|tr ”>” ” ”|sed ’s/< .*//’ | tr -d ’\001’-’\011’’\013’’\014’’\016’-’\037’’\200’-’\377’ |sort -n<h6 class="zemanta-related-title">Related articles by Zemanta <ul class="zemanta-article-ul"> <li class="zemanta-article-ul-li"><a href="http://www.slumpedoverkeyboarddead.com/2009/09/17/use-curl-to-monitor-your-vonage-phone-bill/">Use curl to Monitor Your Vonage Phone Bill (slumpedoverkeyboarddead.com) <li class="zemanta-article-ul-li"><a href="http://securewebs.com/yum-updates/">Yum Updates (securewebs.com) <li class="zemanta-article-ul-li"><a href="http://www.gubatron.com/blog/2009/10/10/ubuntudebian-quick-reference-how-to-change-your-servers-utc-timezone-on-the-command-line/">Ubuntu/Debian Quick Reference: How To Change Your Server’s UTC Timezone on the command line (gubatron.com) <li class="zemanta-article-ul-li"><a href="http://blog.amit-agarwal.co.in/2009/11/22/short-information-about-loaded-kernel-modules/">Short Information about loaded kernel modules (amit-agarwal.co.in) <div class="zemanta-pixie"><a class="zemanta-pixie-a" title="Reblog this post [with Zemanta]" href="http://reblog.zemanta.com/zemified/b22b2e85-8107-4f9b-9130-85a8e8ae370b/"><img class="zemanta-pixie-img" src="http://blog.amit-agarwal.co.in/wp-content/uploads/2010/08/reblog_b52.png" alt="Reblog this post [with Zemanta]" /><span class="zem-script more-related more-info pretty-attribution paragraph-reblog">

Checking the links to your site (from affiliates) using cron and bash script.

Thu, 27 May 2010 20:26:33 +0000

If you have some affiliate links and are concerned about their presence then you can setup <a class="zem_slink freebase/guid/9202a8c04000641f80000000045c9c5b" title="Cron" rel="wikipedia" href="http://en.wikipedia.org/wiki/Cron">cron to check the links for you regularly. For this you need a very simple script (as below) and a cron entry (example further down).

#!/bin/bash –
#===============================================================================

#          FILE: checklinks.sh

#         USAGE: ./checklinks.sh

#   DESCRIPTION: Check if the links exists on affiliate sites

#       OPTIONS: —
# REQUIREMENTS: —
#          BUGS: —
#         NOTES: —
#        AUTHOR: <a class="zem_slink" title="Amit Agarwal" rel="homepage" href="http://amit-agarwal.co.in">Amit Agarwal (AKA), amit.agarwal@amit-agarwal.co.in
#       COMPANY: Individual
#       VERSION: 1.0
#       CREATED: 04/07/2010 08:19:29 AM IST
#      REVISION: —
#===============================================================================

vim - get mappings from the help tex files available with the scripts.

Thu, 27 May 2010 11:44:39 +0000

Here is a simple script that will show all the vim mappings from the tex file (help file that comes with the vim scripts).

This will prove to be very useful in usin gthe mappings 🙂

#!/bin/bash –
#===============================================================================

#          FILE: get_mappings_from_tex_for_vim.sh

#         USAGE: ./get_mappings_from_tex_for_vim.sh

#   DESCRIPTION: Get the mappings from tex file

#       OPTIONS: —
# REQUIREMENTS: —
#          BUGS: —
#         NOTES: —
#        AUTHOR: <a class="zem_slink" title="Amit Agarwal" rel="self" href="http://blog.amit-agarwal.co.in">Amit Agarwal (AKA), amit.agarwal@amit-agarwal.co.in
#       COMPANY: Individual
#       VERSION: 1.0
#       CREATED: 09/06/2009 09:19:19 PM IST
#      REVISION: —
#===============================================================================
file=$1
IFS=$(echo -e ’\n’)
for i in $(cat $file |<a class="zem_slink freebase/en/grep" title="Grep" rel="wikipedia" href="http://en.wikipedia.org/wiki/Grep">grep ”^..line”)
do
#echo $i |<a class="zem_slink freebase/en/awk" title="AWK" rel="homepage" href="http://cm.bell-labs.com/cm/cs/awkbook/index.html">awk -F”’” '{print $2” ” $3” ”$4}’|awk -F”&” '{print $1” ”$2}’
echo $i |awk -F”’” '{
if ( NF >= 4 )
{
print ($2”\t ->”$4”\t==»”$NF);
}
else
{
print($2”\t–>”$3);
}
fi
}’ |<a class="zem_slink freebase/en/sed" title="Sed" rel="wikipedia" href="http://en.wikipedia.org/wiki/Sed">sed ’s/\h.*(/(/’ |sed ’s/>.*&/>/’ |sed ’s/\t*-.>$//’ |sed ’s/\//’

Inotify Example - Introduction to Inotify with a C Program Example

Mon, 24 May 2010 16:25:39 +0000

<a href="http://www.thegeekstuff.com/2010/04/inotify-c-program-example/">Inotify Example: Introduction to Inotify with a C Program Example:

<a class="zem_slink freebase/en/inotify" href="http://en.wikipedia.org/wiki/Inotify" title="Inotify" rel="wikipedia">inotify utility is an effective tool to monitor and notify <a class="zem_slink freebase/en/file_system" href="http://en.wikipedia.org/wiki/File_system" title="File system" rel="wikipedia">filesystem changes. You can specify a list of files and directories that needs to be monitored by inotify. This <a class="zem_slink freebase/guid/9202a8c04000641f8000000000023d0f" href="http://en.wikipedia.org/wiki/Library" title="Library" rel="wikipedia">library is used by various other programs. For example, <a class="zem_slink freebase/en/cpan" href="http://www.cpan.org/" title="CPAN" rel="homepage">CPAN module Linux::Inotify is developed based on this library.
iNotify Execution Flow

LPI Certification help and tutorials

Thu, 20 May 2010 16:43:32 +0000

For the last couple of days I have been very busy but not too away from my desktop. Though I did not get time to publish anything. Here’s one of my other favourite distributions. Its known as elpicx. This distribution is oriented towards LPI certification exams and contains some documents and links that are quite helpful.

Good thing is now it supports F9 with KDE.

I found that the documents in the distro are GPL and thus I dont think that there should be any issue in re-distributing the pdfs and the links, so <a href="http://amit.with-linux.com/elpicx/" target="_blank">here it is. If you find anything in these docs or links that I should not link or upload them, let me know. I wil remove them.

Startup animation and theme for Fedora 12 onwards.

Thu, 20 May 2010 16:43:31 +0000

Since the release of <a class="zem_slink freebase/en/fedora" title="Fedora" rel="homepage" href="http://fedoraproject.org/">Fedora 12, fedora is using plymouth. Plymouth kicks in just after grub and before the Xserver starts.

Description:

Plymouth provides an attractive graphical <a class="zem_slink freebase/en/bootsplash" title="Bootsplash" rel="wikipedia" href="http://en.wikipedia.org/wiki/Bootsplash">boot animation in
place of the <a class="zem_slink freebase/en/text_messaging" title="Text messaging" rel="wikipedia" href="http://en.wikipedia.org/wiki/Text_messaging">text messages that normally get shown. Text
messages are instead redirected to a <a class="zem_slink freebase/en/data_logger" title="Data logger" rel="wikipedia" href="http://en.wikipedia.org/wiki/Data_logger">log file for viewing
after boot.

vim – get names of the scripts and the details from the command line

Wed, 19 May 2010 16:38:42 +0000

For the below commands either you can set the two variables in bold and then run the scripts or change the following in the commands and run the scripts.

If you have html2text installed then you can use this:

wget -o /dev/null -O $script_id_file ’http://www.vim.org/scripts/script.php?script_id=’$script_id |html2text

If you dont have html2text installed then you can use:

wget -o /dev/null -O $script_id_file ’http://www.vim.org/scripts/script.php?script_id=’$script_id<h6 class="zemanta-related-title">Related articles by Zemanta <ul class="zemanta-article-ul"> <li class="zemanta-article-ul-li"><a href="http://www.inquisitr.com/55496/twilight-eclipse-script-allegedly-leaked/">Twilight Eclipse Script Allegedly Leaked (inquisitr.com) <li class="zemanta-article-ul-li"><a href="http://huddledmasses.org/powershell-script-club-in-rochester-on-wednesday/">PowerShell Script Club in Rochester on Wednesday (huddledmasses.org) <li class="zemanta-article-ul-li"><a href="http://blogs.adobe.com/acrolaw/2010/02/add_a_flatten_document_menu_item.html">Add a Flatten Document Menu Item to Acrobat (blogs.adobe.com) <li class="zemanta-article-ul-li"><a href="http://codebetter.com/blogs/james.kovacs/archive/2010/02/25/the-exec-problem.aspx">The Exec Problem (codebetter.com) <div class="zemanta-pixie" style="margin-top: 10px; height: 15px;"><a class="zemanta-pixie-a" title="Reblog this post [with Zemanta]" href="http://reblog.zemanta.com/zemified/d25e9b6c-aca3-4008-9a3c-3403140d32e0/"><img class="zemanta-pixie-img" style="border: medium none; float: right;" src="http://blog.amit-agarwal.co.in/wp-content/uploads/2010/08/reblog_e38.png" alt="Reblog this post [with Zemanta]" /><span class="zem-script more-related pretty-attribution">

Downloading all related videos from youtube with youtube-dl

Sun, 16 May 2010 15:53:16 +0000

How many time did you want to see all the videos (related) to the one you were watching on youtube but decided otherwise as the downloaded was not fast enough. Or has it happened to you that you wanted to <a class="zem_slink freebase/en/uploading_and_downloading" title="Uploading and downloading" rel="wikipedia" href="http://en.wikipedia.org/wiki/Uploading_and_downloading">download all the related videos, in either case you can use the youtube-dl utility I blogged about some times back. First you need to get all the <a class="zem_slink freebase/en/uniform_resource_locator" title="Uniform Resource Locator" rel="wikipedia" href="http://en.wikipedia.org/wiki/Uniform_Resource_Locator">URL’s in a <a class="zem_slink freebase/en/text_file" title="Text file" rel="wikipedia" href="http://en.wikipedia.org/wiki/Text_file">text file, and the simplest way to do this is :

top - looks better and is more useful with a rc file...

Fri, 07 May 2010 03:27:39 +0000

top is a very useful command to find out who is eating up the <a class="zem_slink freebase/en/central_processing_unit" title="Central processing unit" rel="wikipedia" href="http://en.wikipedia.org/wiki/Central_processing_unit">CPU or the memory. But sometimes the plain and simple look simply would be boring so how about some fun. Copy the below code to file : ~/.toprc

RCfile for ”top”
Id:a, Mode_altscr=1, Mode_irixps=0, Delay_time=5.000, Curwin=0
Def   fieldscur=mfcAbdEgHIursOpQTvyzWjKNLX
winflags=32184, sortindx=10, maxtasks=0
summclr=4, msgsclr=5, headclr=5, taskclr=4
Job   fieldscur=ABcefgjlrstuvyzMKNHIWOPQDX
winflags=62777, sortindx=0, maxtasks=0
summclr=6, msgsclr=6, headclr=7, taskclr=6
Mem   fieldscur=ANOPQRSTUVbcdefgjlmyzWHIKX
winflags=62777, sortindx=13, maxtasks=0
summclr=5, msgsclr=5, headclr=4, taskclr=5
Usr   fieldscur=ABDECGfhijlopqrstuvyzMKNWX
winflags=62777, sortindx=4, maxtasks=0
summclr=3, msgsclr=3, headclr=2, taskclr=3

Solved -- Errors with afraid-dyndns in Goddard (Fedora 13)

Thu, 06 May 2010 13:31:17 +0000

Since I updated to the <a class="zem_slink freebase/en/fedora" title="Fedora" rel="homepage" href="http://fedoraproject.org/">Fedora 13, I was getting error from the <a class="zem_slink freebase/en/dynamic_dns" title="Dynamic DNS" rel="wikipedia" href="http://en.wikipedia.org/wiki/Dynamic_DNS">Dynamic DNS client for afraid. I was not getting enough time to fix this, so finally I decided to fix this in the night itself 🙂

Problem:
On running

afraid-dyndns

I was getting the error:

Entity: line 100: <a class="zem_slink freebase/en/parsing" title="Parsing" rel="wikipedia" href="http://en.wikipedia.org/wiki/Parsing">parser error : Opening and ending tag mismatch: br line 99 and div

Lock the hardware eject button of the cdrom

Thu, 29 Apr 2010 14:46:29 +0000

$ eject -i 1 This command will lock the hardware eject button of your cdrom drive. Some uses are:

1: If you have a toddler and has discovered the cdrom button

2: If you are carrying a laptop in a bag or case and don’t want it to eject if the button is inadvertently pressed.

To unlock the button use:

eject -i 0

<a href="http://www.commandlinefu.com/commands/view/5390/lock-the-hardware-eject-button-of-the-cdrom">View this command to comment, vote or add to favourites
<a href="http://feeds2.feedburner.com/commands/by/mdelatorre">View all commands by <a href="http://feeds2.feedburner.com/commands/by/mdelatorre">mdelatorre

String and Array Creation

Wed, 28 Apr 2010 14:23:03 +0000

: Image via Wikipedia

<img src="http://blog.amit-agarwal.co.in/wp-content/uploads/2010/08/perl-one-liners.jpg" alt="Perl One Liners" align="bottom" />This is the fourth part of a nine-part article on famous <a class="zem_slink freebase/en/perl" title="Perl" rel="homepage" href="http://www.perl.org/">Perl one-liners. In this part I will create various one-liners for string and array creation. See <a href="http://www.catonmat.net/blog/perl-one-liners-explained-part-one/">part one for introduction of the series.

Famous Perl one-liners is my attempt to create “perl1line.txt” that is similar to “<a href="http://www.catonmat.net/blog/awk-one-liners-explained-part-one/">awk1line.txt” and “<a href="http://www.catonmat.net/blog/sed-one-liners-explained-part-one/">sed1line.txt” that have been so popular among Awk and Sed programmers.

How To Modify Your Wordpress Theme Via The Browser Using Stiqr

Tue, 27 Apr 2010 16:07:43 +0000

<img src="http://blog.amit-agarwal.co.in/wp-content/uploads/2010/08/00_Stiqr_logo.jpg" alt="00_Stiqr_logo.jpg" width="253" height="114" align="bottom" />Ordinary <a href="http://www.makeuseof.com/tag/how-to-build-a-self-hosted-wordpress-blog-for-free/">self-hosted WordPress users know only too well that even though choosing and using thousands of available themes is a snap, creating one is an almost impossible task. You could use <a href="http://www.makeuseof.com/tag/customize-design-wordpress-theme-easily-constructor/">one of the customizable themes to modify the look to your liking, but that’s as far as you can go. Theme creating is not for the faint-hearted who are afraid to plunge into <a class="zem_slink freebase/en/html" title="HTML" rel="wikipedia" href="http://en.wikipedia.org/wiki/HTML">HTML, <a class="zem_slink freebase/en/php" title="PHP" rel="homepage" href="http://www.php.net/">PHP and <a class="zem_slink freebase/en/cascading_style_sheets" title="Cascading Style Sheets" rel="wikipedia" href="http://en.wikipedia.org/wiki/Cascading_Style_Sheets">CSS coding.

Linux Shell Scripting Tutorial – A Beginner\’s handbook

Sun, 11 Apr 2010 09:11:57 +0000

: Image via Wikipedia

<a class="zem_slink freebase/en/unix_shell" title="Unix shell" rel="wikipedia" href="http://en.wikipedia.org/wiki/Unix_shell">Linux Shell Scripting Tutorial – A Beginner’s handbook —

This book is for students and Linux System Administrators. It provides the skills to read, write, and debug <a title="Linux" href="http://bash.cyberciti.biz/guide/Linux">Linux <a class="zem_slink freebase/en/shell_script" title="Shell script" rel="wikipedia" href="http://en.wikipedia.org/wiki/Shell_script">shell scripts using <a title="Bash" href="http://bash.cyberciti.biz/guide/Bash">bash <a title="Shell" href="http://bash.cyberciti.biz/guide/Shell">shell. The book begins by describing <a title="Linux" href="http://bash.cyberciti.biz/guide/Linux">Linux and simple scripts to automate frequently executed commands and continues by describing conditional logic, <a class="zem_slink freebase/en/interactivity" title="Interactivity" rel="wikipedia" href="http://en.wikipedia.org/wiki/Interactivity">user interaction, loops, menus, traps, and functions. Finally, book covers various sys admin related scripts such as making a backup, using <a class="zem_slink freebase/guid/9202a8c04000641f80000000045c9c5b" title="Cron" rel="wikipedia" href="http://en.wikipedia.org/wiki/Cron">cron jobs, writing interactive tools, web based tools, remote login, ftp and database backup related scripts. This book is intended for Linux <a class="zem_slink freebase/en/system_administrator" title="System administrator" rel="wikipedia" href="http://en.wikipedia.org/wiki/System_administrator">system administrators or students who have mastered the basics of a Linux Operating System. You should be able to:

Script to get the number of events from the logs.

Sun, 11 Apr 2010 09:11:49 +0000

I was trying to do some <a class="zem_slink freebase/en/log_analysis" title="Log analysis" rel="wikipedia" href="http://en.wikipedia.org/wiki/Log_analysis">log analysis and finding the events in the logs. For this the logs had the Events logged as ”|+Event name|” or with sending and receiving. So I wrote this little script to take care of my requirements.

monkeystudio IDE on Fedora 12.. IDE of choice

Tue, 30 Mar 2010 12:05:30 +0000

<a href="http://www.monkeystudio.org/" target="_blank">Monkey IDE is a Free <a class="zem_slink freebase/en/cross-platform" title="Cross-platform" rel="wikipedia" href="http://en.wikipedia.org/wiki/Cross-platform">crossplatform <a class="zem_slink freebase/en/qt" title="Qt (framework)" rel="homepage" href="http://qt.nokia.com/">Qt 4 IDE

MonkeyStudio is a crossplatform <a class="zem_slink freebase/en/integrated_development_environment" title="Integrated development environment" rel="wikipedia" href="http://en.wikipedia.org/wiki/Integrated_development_environment">Integrated Development Environment ( IDE ) aiming to become a <a class="zem_slink freebase/en/rapid_application_development" title="Rapid application development" rel="wikipedia" href="http://en.wikipedia.org/wiki/Rapid_application_development">Rapid Application Development ( RAD ) environment. MonkeyStudio runs everywhere Qt 4.4.0 ( minimum required to build it ) is available as a <a class="zem_slink freebase/en/library" title="Library (computing)" rel="wikipedia" href="http://en.wikipedia.org/wiki/Library_%28computing%29">shared library. It is extensible via a great and powerful <a class="zem_slink freebase/en/plugin" title="Plug-in (computing)" rel="wikipedia" href="http://en.wikipedia.org/wiki/Plug-in_%28computing%29">plugin system which help make it do nearly anything you want and support virtually any kind of project type for which a plugin exists or is created. The primary goal of MonkeyStudio was to manage Qt4 projects as best as possible, it directly uses .pro files and does not create intrusive or unsightly <a class="zem_slink freebase/en/configuration_file" title="Configuration file" rel="wikipedia" href="http://en.wikipedia.org/wiki/Configuration_file">configuration files. MonkyStudio is also a multi language <a class="zem_slink freebase/en/source_code_editor" title="Source code editor" rel="wikipedia" href="http://en.wikipedia.org/wiki/Source_code_editor">code editor too ( javascript, xml, … ).

Search & replace with find & ed

Sun, 28 Mar 2010 11:58:32 +0000

: Image via Wikipedia

function sr() {

declare pattern replacement name usage
declare -i pvar=0 rvar=0 tvar=0

usage='usage: sr [-t ] [-n name] [-p pattern] [-r replacement] [– ] [dir1 dir2 …]'

# cf. <a href="http://bsdpants.blogspot.com/2007/02/option-ize-your-shell-scripts.html">http://bsdpants.blogspot.com/2007/02/option-ize-your-shell-scripts.html

while [[ "${1:0:1}" == '-' ]] ; do

[[ "${1}" == '–' ]] && { shift; break; } # – marks end of options

unbound variable – bash completion not working and having issues with other stuff like command not found.

Tue, 23 Mar 2010 03:29:09 +0000

I generally use vi/vim for all my practical purposes of working with text files. And I have all the vi/vim plugins required to work with the files. This causes the following to be in the skeleton for all the bash scripts that I create:

set -o nounset # Treat unset variables as an error

With this all the unbound variables as errors and was problem with all the shell scripts that was being sourced in the startup of bash. So all I had to do was remove this from all the startup scripts and then from the skeleton of the bash script in vim :).

swaks – Swiff army nife for SMTP

Tue, 09 Mar 2010 03:52:02 +0000

If you are having issues with the <a class="zem_slink freebase/en/simple_mail_transfer_protocol" title="Simple Mail Transfer Protocol" rel="wikipedia" href="http://en.wikipedia.org/wiki/Simple_Mail_Transfer_Protocol">SMTP Server, then sometimes you just wish you had a swiss army knife to test the same and then you would not have to spend your precious time on some silly mistake that you may have made. Your wish is now fulfilled.

<a class="zem_slink freebase/en/military_of_switzerland" title="Military of Switzerland" rel="wikipedia" href="http://en.wikipedia.org/wiki/Military_of_Switzerland">Swiss Army Knife SMTP: A <a class="zem_slink freebase/en/command_line_interface" title="Command-line interface" rel="wikipedia" href="http://en.wikipedia.org/wiki/Command-line_interface">command line SMTP tester. Swaks can test various aspects of your SMTP <a class="zem_slink freebase/en/server" title="Server (computing)" rel="wikipedia" href="http://en.wikipedia.org/wiki/Server_%28computing%29">server, including <a class="zem_slink freebase/en/transport_layer_security" title="Transport Layer Security" rel="wikipedia" href="http://en.wikipedia.org/wiki/Transport_Layer_Security">TLS and AUTH.

Openoffice.org and/or Excel useful tips.

Wed, 10 Feb 2010 15:19:48 +0000

Today I was working on Excel sheets and had to do quite a lot of manipulations. Here are some of those:

Find the value of the cell whose number is stored in another cell.

You can use the indirect function.

Here is example:

That’s cool and easy.

Indirect reference with some constant values.

You can add constant and cell id with ”&”

bash script with sql to get the number of records from multiple tables.

Wed, 10 Feb 2010 15:19:40 +0000

Here is the bash script:

#!/bin/sh
names[1]=errorlog
names[2]=amit1log
names[3]=amit2log
names[4]=amit3log
names[5]=amit4log
j=1
echo $1
for i in $( sqlplus amit/passwd@tns @get_count.sql |sed -n ’/COUNT/,/Disconnected/p’|sed ’/COUNT/ d’|sed ’/—/ d’|sed ’/Disconnected/ d’|tr ’n’ ’ ’ )
do
temp=${names[$j]}
let count=30-${#temp}
for ((I=1; I <= $count ; I++))
do
printf ” ”
done
echo ”${names[$j]} : $i”
# echo $j
let j=j+1
done
echo
echo

and the required sql script:

select count() from errorlog;
select count() from amit1log;
select count() from amit2log;
select count() from amit3log;
select count(*) from amit4log;
quit;

Built-in lists in vim

Wed, 03 Feb 2010 16:49:32 +0000

<a class="zem_slink freebase/en/vimscript" title="Vimscript" rel="wikipedia" href="http://en.wikipedia.org/wiki/Vimscript">Vimscript provides excellent support for operating on collections of <a class="zem_slink freebase/en/data" title="Data" rel="wikipedia" href="http://en.wikipedia.org/wiki/Data">data, a cornerstone of programming. In this third article in the series, learn how to use Vimscript’s built-in lists to ease everyday operations such as reformatting lists, filtering sequences of filenames, and sorting sets of line numbers. You’ll also walk through examples that demonstrate the power of lists to extend and enhance two common uses of <a class="zem_slink freebase/en/vim" title="Vim (text editor)" rel="homepage" href="http://www.vim.org/">Vim: creating a <a class="zem_slink freebase/en/user_defined_function" title="User-defined function" rel="wikipedia" href="http://en.wikipedia.org/wiki/User-defined_function">user-defined function to align assignment operators, and improving the built-in text completions mechanism.

Understand Awk Variables with 3 Practical Examples

Thu, 28 Jan 2010 08:02:21 +0000

<a id="aptureLink_CLV4LbC1Dr" style="padding: 0px 6px; float: right;" href="http://gnuwin32.sourceforge.net/packages/mawk.htm"><img style="border: 0px none;" title="Mawk for Windows" src="http://blog.amit-agarwal.com/wp-content/uploads/img.zemanta.com/ph/400x270_WebClip" alt="" width="400px" height="270px" /> This article is part of the on-going Awk Tutorial and Examples series. Like any other <a class="zem_slink freebase/en/programming_language" title="Programming language" rel="wikipedia" href="http://en.wikipedia.org/wiki/Programming_language">programming languages, Awk also has user defined variables and built-in variables. In this article let us review how to define and use <a class="zem_slink freebase/en/awk" title="AWK" rel="homepage" href="http://cm.bell-labs.com/cm/cs/awkbook/index.html">awk variables. Awk variables should begin with the letter, followed by it can consist of alpha numeric characters or underscore. Keywords […]

Seders\’s grab bag – Tutorials

Sun, 24 Jan 2010 15:45:56 +0000

<a href="http://sed.sourceforge.net/grabbag/tutorials/">http://sed.sourceforge.net/grabbag/tutorials/

<span style="font-size: x-large;"><a href="http://sed.sourceforge.net/grabbag/">seder’s<a href="http://sed.sourceforge.net/grabbag/"> grab bag

<a href="http://sed.sourceforge.net/grabbag/scripts/">scripts
<a href="http://sed.sourceforge.net/grabbag/tutorials/">tutorials
<a href="http://sed.sourceforge.net/grabbag/seders/">seders
<a href="http://sed.sourceforge.net/grabbag/ssed/">ssed
<a href="http://sed.sourceforge.net/grabbag/links/">links
<a href="http://sed.sourceforge.net/grabbag/tutorials/#intros">Intros
<a href="http://sed.sourceforge.net/grabbag/tutorials/#advanced">Advanced
<a href="http://sed.sourceforge.net/grabbag/tutorials/#misc">Miscellaneous

<span style="font-size: large;">Sed Tutorials

If you have written anything about sed – whether an introduction, how sed got you out of a real-life situation, or perhaps an advanced technique you’ve discovered – you may like have your work published here. <a href="mailto:bonzini@gnu.org">Your contribution will be very welcome.

Perl script to create csv files with a pattern – Generic script.

Tue, 19 Jan 2010 03:11:16 +0000

I was having a really bad day and needed a quick solution to create some csv files. And this I needed to do for multiple data kinds and patterns, so I created this small script to do the job for me…

#Number of rows required in the output.

$rows = 100;

#The config and the output file

open (CF_FILE, ”<Config.test”);
open (OUT_FILE, ”>test.csv”);

#—————————————————————————
# No need to change anything below this.
#—————————————————————————

Opens Four Google Frames At Once

Sat, 19 Dec 2009 07:51:49 +0000

: Image via Wikipedia

Googlegooglegooglegoogle: Opens Four <a class="zem_slink" title="Google" rel="homepage" href="http://google.com">Google Frames At Once Googlegooglegooglegoogle (that is Google times 4!) is a simple <a class="zem_slink" title="Website" rel="wikipedia" href="http://en.wikipedia.org/wiki/Website">website/<a class="zem_slink" title="Homepage" rel="wikipedia" href="http://en.wikipedia.org/wiki/Homepage">startpage that puts four Google search windows in one page. It basically displays four frames so that you do not have to leave the page to search simultaneously. This tool is incredibly useful for Google power searchers.
<img src="http://blog.amit-agarwal.co.in/wp-content/uploads/2010/08/g4_thumb.png" alt="" align="bottom" />

check out http://browsershots.org/

Sat, 19 Dec 2009 07:49:06 +0000

If you are a web developer and are worried about how your <a class="zem_slink" href="http://en.wikipedia.org/wiki/Website" title="Website" rel="wikipedia">website would look like in the various browsers and do not have the resources to test all the browsers, what do you do? Check out the <a class="zem_slink" href="http://en.wikipedia.org/wiki/Web_page" title="Web page" rel="wikipedia">webpage at

<a href="http://browsershots.org/">http://browsershots.org/<h6 class="zemanta-related-title">Related articles by Zemanta <ul class="zemanta-article-ul"> <li class="zemanta-article-ul-li"><a href="http://www.macstories.net/iphone/website-iphone/">Setting Up Your Website to Run on iPhone Browser (macstories.net) <div class="zemanta-pixie"><a class="zemanta-pixie-a" href="http://reblog.zemanta.com/zemified/8d5363f4-7641-40c8-b111-4a4d12d41ba5/" title="Reblog this post [with Zemanta]"><img class="zemanta-pixie-img" src="http://blog.amit-agarwal.co.in/wp-content/uploads/2010/08/reblog_e36.png" alt="Reblog this post [with Zemanta]" /><span class="zem-script more-related more-info pretty-attribution paragraph-reblog">

Some good and nice open source books worth downloading.

Sun, 22 Nov 2009 15:03:46 +0000

There is a nice article <a href="http://www.tectonic.co.za/?p=4491" target="_blank">here b<span class="byline">by Alastair Otter. He has given links to different Books that are worth reading. These include:

<span class="byline">1)<a href="http://oreilly.com/catalog/9780596517984/" target="_blank"> http://oreilly.com/catalog/9780596517984/

<span class="byline">2) <a href="http://en.flossmanuals.net/DigitalFoundations" target="_blank">http://en.flossmanuals.net/DigitalFoundations

<span class="byline">3) <a href="http://wiki.blender.org/index.php/Doc:Tutorials/Animation/BSoD/Character_Animation" target="_blank">http://wiki.blender.org/index.php/Doc:Tutorials/Animation/BSoD/Character_Animation

<span class="byline">4) <a href="ftp://ftp.heanet.ie/pub/debian/pool/non-free/r/rutebook/" target="_blank">ftp://ftp.heanet.ie/pub/debian/pool/non-free/r/rutebook/

<span class="byline">to name a few, along with others. Its worth reading the article. While you are at it don’t forget the gems known as comments.

Multiple search in vim

Thu, 19 Nov 2009 02:02:19 +0000

I was looking at a log file and needed to highlight multiple search items to make the logs more readable. I got into multiple threads suggesting various cryptic vim commands but I was in no mood to remember them. So, I finally hit <a href="http://www.vim.org/scripts/script.php?script_id=479" target="_blank">this.

This is a cool vim script which you can use to highlight multiple search patter. You can simply add a search term by doing

Calculations

Tue, 17 Nov 2009 14:18:34 +0000

<img src="http://blog.amit-agarwal.co.in/wp-content/uploads/2010/08/perl-one-liners.jpg" alt="Perl One Liners" align="bottom" />This is the third part of a seven-part article on famous Perl one-liners. In this part I will create various one-liners for calculations. See <a href="http://www.catonmat.net/blog/perl-one-liners-explained-part-one/">part one for introduction of the series.

The article on famous Perl one-liners will consist of at least seven parts:

bash tutorial for begineer and experienced.

Mon, 20 Jul 2009 15:42:22 +0000

I having been looking for something like this for sometime. Found <a href="http://beginlinux.com/desktop_training/comm/shells/232-bash" target="_blank">this while searching.

A very good thing about this tutorial is its comprehensiveness and the details. A lot of examples are gives which too are quite useful.

Learning on Amit Agarwal Linux Blog

Hackernews In Your Inbox

Firefox addons for hacking

Creating and using ackrc

mussh-run-commands-on-multiple-hosts

virt-install with cloud-init

Stay safe from phising

Curl to exapnd short url

Sleep infinitely in bash

Ignore case when completing file names in bash

Warn when battery is low

Some good find alias.

Books menu with bash

Podman repositories on ubuntu like distros

Pygmentize Styles

scripting – performance improvement with file open

List all the tags for a image on docker hub

kitty terminal themes

unicode characters in urxvt terminal

Get the git url of current repo in clipboard

Script to try various themes from kitty terminal

i3 – show mapped hotkeys

check hard disk rpm or rotation speed

ssh trick – ssh to remote host with bastion host

Check your session type – wayland or X11

Running dnsmasq with NetworkManager in Fedora

Split pcap to multiple files based on number of packets

copy /proc folder

cool sed/grep magic to convert output to csv format

bash function for rpm whatprovides

xev – Check the X keyboard events

ranger – try terminal file manager

Display IP address in console login screen

Port php mysql scripts to php 7.0 from 5.x version

Monitor progress of coreutils commad like mv, cp etc

Send history of current host to some other host over ssh

Fix display size on libvirt/Qemu guest

Getting Started with Elixir Programming Language

Fix weird flux menu

Related articles across the web

scapy packet dump to packet

Kernel dropped packet analysis

Get kernel function name from kernel address.

Compose a video from a text sequence

xsos – a tool for sysadmins and support

git – plot the history

DNS – simple and effective guide with history

virsh – show ip address of all running VMs

Disk usage by file type

terminal, terminal everywhere.

Executing commands on multiple hosts

retext – Editor for restructured text

ionice – renice you IO activity for the process.

Fedora/Ubuntu issue with assigned IP by dhcp server.

ssh authorized keys – limit ssh session to custom command

script to get hard disk health in fedora/ubuntu

ncurses based eFTE editor – programmers lightweight editor

Multiple entry in .ssh/config file

Debuggging bash cron scripts.

ldap search function

rfc2html – php script to view rfc with index and links.

Some nice linux tutorials

get the contents of whole site like some wiki or wikia

inotify -watch for file to change

Related articles

cgroups – use to control your cpu and memory

Fix typescript files generated with script command

LibreOffice – Formulae Auditing

Related articles

cksum – compare for multiple files.

Related articles

dnsmasq not starting from NetworkManager with SELinux enabled.

ssh reverse tunning..

dnsmasq – use with Network Manager.

Music players on Linux – the poor mans random song player.

Array of all possible colors in bash script

colors in bash scripts

Your own local search engine.

Setup your own RFC Editor for Linux.

Using file partially for filenames