.bashrc and Environment Customization

The .bashrc file is a script that is executed every time a new Bash shell session is started for an interactive user. This file contains various settings and customizations that affect the behavior of the shell. It’s typically located in the home directory (~/.bashrc), and you can edit it to set environment variables, define custom functions, or tweak other shell settings.

The .bashrc file is loaded automatically when you start a terminal. After making changes, you can reload it by running:

source ~/.bashrc

Customizing .bashrc

Custom variables can be set in ~/.bashrc that will be available in all scripts and shell sessions.

export MY_VAR="some value"
export SCRATCH="/scratch/$USER"

Note

In ~/.bashrc, you must export the variable to make it available in scripts and child processes.

Making changes to $PATH

$PATH defines the directories that the shell searches when you run a command. These directories are a colon separated string that is searched from left to right. View your current $PATH with:

echo $PATH

If you want to add a directory to your $PATH, update the variable in your ~/.bashrc.

export PATH=$PATH:~/bin
export PATH=$PATH:~/.local/bin

Warning

Be careful changing the value of $PATH. Always make sure to include the current value in your new value, or else you might lose access to builtin commands.

If not making changes to $PATH, you will need to provide a full path to the executable you wish to run. Without the full path, the shell will search the $PATH and return “Command Not Found”. For example, if you’re trying to run the bash script run.sh that is located at /home/$USER/scripts/run.sh, you can do so in the following ways:

If your current working directory is /home/$USER/scripts:

./run.sh

Otherwise:

/home/$USER/scripts/run.sh

As you can see, adding ~/scripts to your $PATH can eliminate the need to enter the full path to the script and allow you to run the script from any directory. You can add additional scripts to that folder and run them without making other changes.