Setting up a custom bash prompt

If you spend a lot of time exploiting the terminal not only on a single PC, but also on other servers via ssh, it is a good practice to have your bash prompt properly configured. If all your command prompts looks like this (example):

~ chriss $ 

it's almost impossible to determine your current location (server, directory, only a user - which may be common for all machines). The whole magic behind bash prompt configuration is in the $PS1 environment variable. There are also variables $PS2, $PS3, $PS4, but $PS1 is used as the primary bash prompt string. 

So let's create two prompts, one for each server your are usually connecting via ssh, and one for your local machine. Lets look at the possibilities : 

• \d : string date representation
• \e : an escape character
• \h : hostname sub-domain
• \H :  full hostname domain
• \j : current job count
• \n : newline character
• \t : time  / 24h HH:MM:SS
• \T : time / 12h HH:MM:SS
• \@ : time / 12h HH:MM
• \A : time / 24h HH:MM
• \u : username
• \w : current directory relative to $HOME
• \W : current directory

 There are more options to configure the prompt, but I personally find these most useful. Let's start with the local machine. Well since it's the default place you'll be starting your adventure from, and you'll eventually return to this prompt after your job on remote machines is done I suggest skipping most information and keeping the prompt something like this:

export PS1="~ \u \w $"

Which results in:

~ kr ~/prj/python $

It's easy, if you don't see no hostname on the prompt, you're probably still on the local machine. Displaying the working directory may save you a lot of ls / pwd executions. 

If you're connected to a remote machine, it's best to have a greater context. A good option beside the username i the hostname (full if you're having problems differentiating remote machines using only the first subdomain), the current working directory has proven useful not only on remote machines, and finally - if you're connecting to different time zones, it's a good idea to display the system time. Summing up, we would end up with something like this:

export PS1="[\A] \u@\H \W $"

This will result in the following prompt message:

[21:45] kr@some.secret.server current_dir $

This way you will never get confused about your terminal session. Remember that this only sets the prompt for the current session, if you want your prompt to get configured every time you start a session, you should apply this code to your ~/.bashrc file.

 Cheers!

~KR