Grep on Amit Agarwal Linux Blog

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.

using cat with grep – why?

Mon, 06 Jan 2020 01:01:27 +0000

GREP_COLORS – change the colors in the GREP output.

Mon, 22 Apr 2019 01:00:59 +0000

Today we will look at the variable GREP_COLORS. This variable determines the colour that is used with the grep command. You can look at the man page of the grep command to see what the various options mean. Here is the excerpt from the man command:

GREP_COLORS

          Specifies the colors and other attributes used to highlight various  parts  of  the
          output.   Its  value  is  a  colon-separated  list of capabilities that defaults to
          ms=01;31:mc=01;31:sl=:cx=:fn=35:ln=32:bn=32:se=36  with  the  rv  and  ne   boolean
          capabilities omitted (i.e., false).  Supported capabilities are as follows.

          sl=    SGR  <a class="zem_slink" title="Substring" href="http://en.wikipedia.org/wiki/Substring" rel="wikipedia">substring</a>  for  whole  selected lines (i.e., matching lines when the -v
                 command-line option is omitted, or non-matching lines when -v is specified).
                 If however the boolean rv capability and the -v command-line option are both
                 specified, it applies to context matching lines  instead.   The  <a class="zem_slink" title="Default (finance)" href="http://en.wikipedia.org/wiki/Default_%28finance%29" rel="wikipedia">default</a>  is
                 empty (i.e., the terminal's default color pair).

          cx=    SGR  substring for whole context lines (i.e., non-matching lines when the -v
                 command-line option is omitted, or matching lines when -v is specified).  If
                 however  the  boolean  rv capability and the -v command-line option are both
                 specified, it applies to selected non-matching lines instead.   The  default
                 is empty (i.e., the terminal's default color pair).

          rv     <a class="zem_slink" title="Boolean data type" href="http://en.wikipedia.org/wiki/Boolean_data_type" rel="wikipedia">Boolean  value</a>  that  reverses  (swaps)  the  meanings  of  the  sl= and cx=
                 capabilities when the -v command-line option is specified.  The  default  is
                 false (i.e., the capability is omitted).

          mt=01;31
                 SGR  substring  for  matching  <a class="zem_slink" title="Empty set" href="http://en.wikipedia.org/wiki/Empty_set" rel="wikipedia">non-empty</a>  text in any matching line (i.e., a
                 selected line when the -v command-line option is omitted, or a context  line
                 when  -v  is specified).  Setting this is equivalent to setting both ms= and
                 mc= at once to the same value.  The default is a bold  red  text  foreground
                 over the current line background.

          ms=01;31
                 SGR substring for matching non-empty text in a selected line.  (This is only
                 used when the -v command-line option is omitted.)  The effect of the sl= (or
                 cx=  if  rv) capability remains active when this kicks in.  The default is a
                 bold red text foreground over the current line background.

          mc=01;31
                 SGR substring for matching non-empty text in a context line.  (This is  only
                 used  when  the -v command-line option is specified.)  The effect of the cx=
                 (or sl= if rv) capability remains active when this kicks in.  The default is
                 a bold red text foreground over the current line background.

          fn=35  SGR  substring  for file names prefixing any content line.  The default is a
                 magenta text foreground over the terminal's default background.

          ln=32  SGR substring for <a class="zem_slink" title="Line number" href="http://en.wikipedia.org/wiki/Line_number" rel="wikipedia">line numbers</a> prefixing any content line.  The default is a
                 green text foreground over the terminal's default background.

          bn=32  SGR substring for byte offsets prefixing any content line.  The default is a
                 green text foreground over the terminal's default background.

          se=36  SGR substring for separators that are inserted between selected line  fields
                 (:),  between context line fields, (-), and between groups of adjacent lines
                 when nonzero context  is  specified  (--).   The  default  is  a  cyan  text
                 foreground over the terminal's default background.

          ne     Boolean  value that prevents clearing to the <a class="zem_slink" title="Newline" href="http://en.wikipedia.org/wiki/Newline" rel="wikipedia">end of line</a> using Erase in Line
                 (EL) to Right (\33[K) each time a colorized item ends.  This  is  needed  on
                 terminals on which EL is not supported.  It is otherwise useful on terminals
                 for which the back_color_erase (bce) boolean terminfo  capability  does  not
                 apply,  when  the  chosen  highlight colors do not affect the background, or
                 when EL is too slow or causes too much flicker.  The default is false (i.e.,
                 the capability is omitted).

Get count of lines in scripts (shell)

Thu, 15 Oct 2015 00:41:52 +0000

If you have tried to get the count of lines in file, the you would know about “nl” or “wc -l”. But as you are aware these give you number of lines with other details as well and you need to post process the number to make sure that you have only number and nothing else. In such cases, it is useful to use the count feature of grep and here is a shorthand to get the count of lines in any shell script:

nice little bash function to search for running processes

Mon, 13 Oct 2014 00:20:31 +0000

Here is a nice little handy function that I use very regurlarly.

You can use this function with parameter to just grep for that or just type psa to see all the running processes.

Just put this in your .bashrc file.

You might find it useful:

psa () 
{ 
    if [[ $1 == "" ]]; then
        ps -eaf;
    else
        ps -eaf | grep --color=auto -i $1;
    fi
}

Raspberry Pi automate certain tasks – script example

Mon, 10 Mar 2014 01:41:45 +0000

Now, if you have followed these :

fetchmail

ssmtp

Then you already have a working system for sending and receiving mail. Now, you can set the mda in the fetmailrc to a script which can do few things for you. The script below will get a page and mail it to you, if you have the subject as “get” and send “wake on LAN” to desired PC if you have subject as “wol”. Cool 🙂

Apache server stats with small and useful bash script.

Fri, 29 Nov 2013 01:35:36 +0000

Just copy this script to your web-server cgi-bin directory and enjoy.

The script with show the common errors like 404 Error, Internal Server Error and others. It will show the User agent distribution using simple commands like grep, uniq, awk and so on.

You would need to change the tfile – which is temporary file and also the access.log path in the next line.

Just re-direct the output to some file with html extenstion. You could even put this in the cron which re-directs the output to some html in server document root.

bash – using the vi mode more effectively.

Fri, 22 Nov 2013 01:50:24 +0000

Vi blogging bundle (Photo credit: pedro mg)

You can first set the bash mode to vi. This will enable some vim like features to bash. So, add this to .bashrc :

set -o vi

Once, you have done that then its time to get more out of the vi mode. First, check some things and set some interesting stuff.

Check all vim colorschemes for minor issues

Thu, 10 Oct 2013 01:13:25 +0000

Here is script that checks all the colorschemes in the current directory and corrects them if possible (Processing of the file is done with simple commands like sed, grep)

Checks that the color_name is same as Filename

Here is the script:

#!/bin/bash -
#===============================================================================
#
#          FILE: check_colors.sh
#
#         USAGE: ./check_colors.sh
#
#   DESCRIPTION:
#
#       OPTIONS: ---
#  REQUIREMENTS: ---
#          BUGS: ---
#         NOTES: ---
#        AUTHOR: Amit Agarwal (aka), 
#      REVISION:  ---
#===============================================================================
cd ~/.vim/colors
for i in *vim
do
    #echo "Processing $i"
    if [[ $(grep -c g:colors_name $i ) -eq 0 ]]; then
        if [[ $(grep -c colors_name $i ) -eq 0 ]]; then
            echo "File $i does not have colorname";
            missing=$missing" $i"
        else
            sed -i.bak '/colors_name/ s/.*/let g:colors_name="'${i//.vim}'"/g' $i
        fi
    else
        if [[ $(grep -c colors_name $i|grep let ) -gt 1 ]]; then
            echo "WARN ----->> File $i has more than one colorsname"
        fi
        colorname=$(grep g:colors_name $i|grep let| sed -e 's/"//g' -e 's/.*=//' |tr -d ' ')
        if [[ ${colorname}.vim != $i ]]; then
            echo "Filename $i does not match colorname $colorname .. correcting "
            sed -i.bak '/colors_name/ s/.*/let g:colors_name="'${i//.vim}'"/g' $i
            #sed -i.bak 's/(.*g:colors_name.*=)/1'${i//.vim}'/g' $i
        fi
    fi
done

if [[ x$missing != x ]] ; then
    echo "Missing colornames in $missing"
fi

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.

Disable a few cores when you want to save power.

Fri, 28 Dec 2012 01:23:46 +0000

If you have a lot of CPU power and working on battery. If you do not need that much of power and would like to rather save some battery power by disabling some cpus then you can use the below script. This script disables cpus from 4 to 7. You can change the number in the for loop. You would need the sudo to be setup or remove sudo and run the script as root. The script will show you the currently active cpu’s before and after disabling the CPU’s.

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 🙂

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)

some interesting alias

Tue, 27 Sep 2011 07:43:01 +0000

For this time, I will just give you a link to to bashrc file.

http://hayne.net/MacDev/Bash/aliases.bash

Head over there and see some very interesting aliase’s.

Bryan Quigley: Windows Cant Handle the Hardware (bryanquigley.com)
semantic grep (github.com)
Aliases and shortcuts (macstarter.com)

Total upload and download on any interface.

Sun, 05 Jun 2011 01:29:21 +0000

Something that I have been searching for a long time, finally some look inside the <a class=“zem_slink” title=“Procfs” rel=“wikipedia” href=“http://en.wikipedia.org/wiki/Procfs" _mce_href=“http://en.wikipedia.org/wiki/Procfs">/proc got me what I wanted. Hope this will save someone’s day. So far, the only option I could think of was to run conky which becomes a little heave on some of the very old laptops I have to use sometimes 🙁

  <td>
    <div class="text codecolorer">
      &nbsp;cat /proc/net/dev|grep eth2|awk '{print $2/1024/1024"&nbsp; "$10/1024/1024}'
    </div>
  </td>
</tr>

CPUSPEED Slowing you down? (jarneil.wordpress.com)
Interface Curmudgeons versus Gestures (lingpipe-blog.com)
Alias in .bashrc (michaeldaranto.wordpress.com)

Ranking of the most frequently used commands

Mon, 31 Jan 2011 22:54:43 +0000

Lets take a quick look at how to get the most frequently used commands on you shell. So what we need to do is this:

  <td>
    <div class="text codecolorer">
      history | awk '{print $2}' | awk 'BEGIN {FS="|"}{print $1}' | sort | uniq -c | sort -n | tail | sort -nr
    </div>
  </td>
</tr>

So, how did we arrive at this and will this always work? No it might not always work. A typical example is where HISTTIMEFORMAT variable is set. In that case, if you check history, you will see that after the number column we have time and date in the specified format, in which case, you will get wrong information from the above command. Anyways, forgetting these special cases, lets go to how we got this command:

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.

function for copy files with progress bar (using pv – pipe viewer)

Thu, 11 Nov 2010 03:43:43 +0000

function for copy files with progress bar (using pv – pipe viewer)

  <td>
    <div class="text codecolorer">
      &nbsp;cp_p() { if [ `echo "$2" | grep ".*/$"` ]; then pv "$1" > "$2""$1"; else pv "$1" > "$2"/"$1"; fi; }
    </div>
  </td>
</tr>

dont have to type new file name (it copy file under same name) and dont have to use ‘/’ in the end of destination folder (but you can if u want, its idiot proof)

Remove some path from the PATH variable temporarily.

Sat, 04 Sep 2010 15:02:08 +0000

How many times has it happened to you that you are working on some linux platform (like Fedora/Ubuntu/CentOS etc) and suddenly you see that you need to remove some path from the PATH variable so that a script is executed from some other path. It really difficult to do this if the path is too long and if you end up doing this couple of times. If that is the case, then the below script is for you 🙂

regular expression, sed and grep tuturials and tricks.

Thu, 17 Jun 2010 15:56:53 +0000

Simply a great one page article on sed and use of regular expressions.

<a href="http://almirkaric.com/2009/07/15/sed-and-grep-tips/" target="_blank">http://almirkaric.com/2009/07/15/sed-and-grep-tips/

Determine what process is listening on a port on Solaris, without lsof

Tue, 08 Jun 2010 09:13:37 +0000

: Image by Metsuke iLife via Flickr

$ for x in `ptree | <a class="zem_slink freebase/en/awk" title="AWK" rel="homepage" href="http://cm.bell-labs.com/cm/cs/awkbook/index.html">awk '{print $1}’`; do pfiles $x | <a class="zem_slink freebase/en/grep" title="Grep" rel="wikipedia" href="http://en.wikipedia.org/wiki/Grep">grep ${PORT} > /dev/null 2>&1; if [ x”$?” == ”x0” ]; then ps -ef | grep $x | grep -v grep; fi; done 2> /dev/null

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">

more powerful grep – ack

Wed, 26 May 2010 11:41:56 +0000

For last couple of days, I have been using ack instead of grep. Here is description of ack:

Ack is designed as a replacement for grep.

There are couple of reasons I am using ack. First and foremost being it does not require a filename. So, for seaching amit in all files recursively under the current directory I can simply use

ack amit

More reasons to use ack:

It supports pager option and there can be a rc file that can be used to define the default options that needs to be used with ack. Here is the contents of my $HOME/.ackrc file.

Script to download all the related videos from youtube with youtube-dl

Mon, 17 May 2010 15:59:20 +0000

Lets cut the long discussion <a class="zem_slink freebase/en/short_subject" title="Short film" rel="wikipedia" href="http://en.wikipedia.org/wiki/Short_film">short and directly give you the script. The script is combination of all the posts that I did in the past about youtube <a class="zem_slink freebase/en/uploading_and_downloading" title="Uploading and downloading" rel="wikipedia" href="http://en.wikipedia.org/wiki/Uploading_and_downloading">downloads. You need to copy 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 file called ”~/youtube.urls” which you want to be downloaded. Or if you need to donwload the related videos, then save the html of the page and give it as the first argument for the script. So, here’s the scrit:

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 :

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.

Extract all urls from the last firefox sessionstore.js file used.

Mon, 29 Mar 2010 07:01:08 +0000

: Image via Wikipedia

Some taken from commandlinefu. What all the below commands are doing is basically that the url: is captured from the sessionstore.js file and then just extract the URL from the line. These are done in various ways using perl, <a class="zem_slink freebase/en/sed" title="Sed" rel="wikipedia" href="http://en.wikipedia.org/wiki/Sed">sed and <a class="zem_slink freebase/en/awk" title="AWK" rel="homepage" href="http://cm.bell-labs.com/cm/cs/awkbook/index.html">awk:

vim search multiple files

Thu, 25 Mar 2010 02:41:28 +0000

Searching some pattern in multiple files is something that is required very often. There are multiple ways to do it, like <a class="zem_slink freebase/en/grep" title="Grep" rel="wikipedia" href="http://en.wikipedia.org/wiki/Grep">grep, <a class="zem_slink freebase/guid/9202a8c04000641f8000000006b66ec6" title="Ack (command-line utility)" rel="wikipedia" href="http://en.wikipedia.org/wiki/Ack_%28command-line_utility%29">ack, find and so on so forth. But if your editor already has the capability to do that, then why leave your favourite vi and go to shell. I will point you to some scripts and some wiki pages on how to do this 🙂

Color in grep output to distinquish the matching entries

Thu, 04 Feb 2010 15:58:35 +0000

Most of the times I end up spending a lot of time to look for the string in the grep output when I do a search. This is quite frustrating and thus I looked at the options for grep command that would make my life easier and there definately is something. Here it is:

export GREP_COLOR=”5;36”

But for this to work you would still need to give the ”–color=auto” option in the grep command. There are two ways to do this, create a alias for grep as ”grep –color=auto” or specify the same in GREPOPTIONS.

grep -v with multiple patterns.

Mon, 25 Jan 2010 15:10:33 +0000

$ sed '/test/{/error|critical|warning/d}' somefile If you wanted to do all in one command, you could go w/ sed instead

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by David Winterbottom (<a href="http://codeinthehole.com">codeinthehole.com)

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