Bash – How to Find the Version of Bash Running

Make sure all non-printable bytes in your PS1 are contained within \[ \]. Otherwise, bash will count them in the length of the prompt. It uses the length of the prompt to determine when to wrap the line.

For example, here bash counts the prompt as 19 columns wide, while the prompt displayed by the terminal is only 10 columns wide (My prompt written in cyan, and > written in default color):

PS1='\e[36mMy prompt\e[0m>'         # bash count: 19, actual: 10

while here it only counts the prompt as 10 columns wide because it ignores the bytes between the special \[ and \] escapes:

PS1='\[\e[36m\]My prompt\[\e[0m\]>' # bash count: 10, actual: 10

For good practice though, use tput to generate the terminal escapes rather than hard coding them:

cyan=$(tput setaf 6) # \e[36m
reset=$(tput sgr0)   # \e[0m
PS1='\[$cyan\]My prompt\[$reset\]>'

See http://mywiki.wooledge.org/BashFAQ/053, and also http://wiki.bash-hackers.org/scripting/terminalcodes for more on tput.

Well there are multiple ways to find the kernel version

Open terminal and execute:

uname -r

It would display something like:

3.8.0-30-generic

You can get further information on the current kernel with

uname -a

It would display something like:

Linux saurav-P4I45Gx-PE 3.8.0-30-generic #44~precise1-Ubuntu SMP Fri Aug 23 17:33:45 UTC 2013 i686 i686 i386 GNU/Linux

Another way to know the kernel version is to open Synaptic Package Manager and search for linux image. You have to check for the installed Kernel version.

Another way to find version of installed kernels is to run this command:

dpkg -l | grep linux-image | grep ii

or for just the version strings:

dpkg -l | grep linux-image | grep ii | awk '{print $3}'

The latest kernel (the one with the highest version number) will boot by default, so if you have rebooted since the last kernel update, and you have not made adjustments to boot into a kernel other than the default, then you can be reasonably confident that the highest version number displayed will be the version of the running kernel, but you should use uname for more reliable information.