How to verify sha256sum for multiple file or one file.

So, lets say you have downloaded the SHA256SUMS files. This file contains the sha256sum for multiple files and you want to compare the values for only one or some of them, then the simplest thing you can do is:

sha256sum -c SHA256SUMS

Now, with this if you do not have some files present then you might get some errors and if you do not want that, then you can try this:

Get count of lines in scripts (shell)

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:

Text file based presentation tool – pinpoint

Pinpoint description:

Name        : pinpoint

Summary     : A tool for making hackers do excellent presentations

URL         : https://live.gnome.org/Pinpoint

License     : LGPLv2+

Description : Pinpoint a simple presentation tool that hopes to avoid audience death

by bullet point and instead encourage presentations containing

beautiful images and small amounts of concise text in slides.

Pinpoint is a presentation tool. The source file for the presentation is text file and thus very easy to manage. You can see an example with :

Executing commands on multiple hosts

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

Network Manager post-up script (dispatcher script)

Network manager is supposed to be much better than network, how so?

it supports dnsmasq for one…

Dnsmasq with netowrkmanager

Local name resolution

Also Network Manager supports dispatcher scripts. How can that help? For one, I used to send interface up emails. To do so, all I had to do was put the following script in “/etc/NetworkManager/dispatcher.d”

#!/bin/sh

cd /etc/sysconfig/network-scripts
. ./network-functions

[ -f ../network ] && . ../network

# Notify programs that have requested notification
IF=$1
STATUS=$2

cat

dnsmasq local name resolution with NetworkManager

Network Manager suports starting dnsmasq which helps you have a local cache for DNS thus getting faster resolution for the DNS queries.

Dnsmasq with netowrkmanager

So, one thing that I have been thinking about is having a local name resolution for the VMs. So, I wanted something like this to work:

vm1 => 172.17.42,1

vm2 => 172.17.42,2

and so on …

To achieve this and reverse dns to work, we will add the entries in file “/etc/NetworkManager/dnsmasq.d/hostnames“. Just one more problem, adding so many entries manually? So, to help you with that, I created this small script:

bash – expand shell variables ( bash bug resolved )

As you would have noticed in the recent versions of bash, expansion does not work properly when expanding directory names. So, for something like this

cd $varname

if you press tab, then variable name does not expand properly.

If this is something that is bothering you then you can now add the following in your bashrc and revert to older behaviour:

shopt -s direxpand

Hope this helps you.