What is .bash_profile?

The .bash_profile is a script that runs whenever you start a new shell session, if you’re using Bash as your default shell. This file is located in your home directory and is used to configure your shell session. It can contain various commands to set environment variables, define functions, adjust the command prompt, set aliases, and more.

It’s important to note that .bash_profile is only run for login shells (i.e., shells that are started when you log in to your system). For non-login shells, Bash runs .bashrc instead. Some users choose to source .bashrc from their .bash_profile to ensure that the same configurations are applied to both login and non-login shells.

Here’s a simple example of a .bash_profile file:

# .bash_profile

# Get the aliases and functions
if [ -f ~/.bashrc ]; then
	. ~/.bashrc
fi

# User specific environment and startup programs
PATH=$PATH:$HOME/bin

export PATH

This .bash_profile does a few things:

• It first checks if a file named .bashrc exists in the home directory. If it does, it sources it. This means it runs the file in the current shell, not a subshell, so any changes made in .bashrc will affect the current shell.

• Then it adds $HOME/bin to the PATH. The PATH is an environment variable that tells your shell where to look for programs to run. So if you have scripts in $HOME/bin, you can run them from anywhere.

• Finally, it exports the PATH, making the changes available to all child sessions initiated from this session. This means any terminal sessions you start from this session will have the updated PATH.

Remember, this is just an example. Your .bash_profile can contain other environment variables, functions, and commands depending on your needs.