.Bashrc Vs .Bash_profile 

In this article, we will talk about the Bash startup files and the difference between the .bashrc and .bash_profile files.

Interactive Login and Non-Login Shell

When invoked, Bash reads and executes commands from a set of startup files. What files are read depends upon whether the shell is invoked as an interactive login or non-login shell.

A shell can be interactive or non-interactive.

In simple terms, an interactive shell is a shell that reads and writes to a user’s terminal, while a non-interactive shell is a shell that is not associated with a terminal, like when executing a script.

A login shell is invoked when a user login to the terminal either remotely via ssh or locally, or when Bash is launched with the –login option. An interactive non-login shell is invoked from the login shell, such as when typing bash in the shell prompt or when opening a new Gnome terminal tab.

Bash Startup Files

When invoked as an interactive login shell, Bash looks for the /etc/profile file, and if the file exists , it runs the commands listed in the file. Then Bash searches for ~/.bash_profile, ~/.bash_login, and ~/.profile files, in the listed order, and executes commands from the first readable file found.

When Bash is invoked as an interactive non-login shell, it reads and executes commands from ~/.bashrc, if that file exists, and it is readable.

Difference Between .bashrc and .bash_profile

.bash_profile is read and executed when Bash is invoked as an interactive login shell, while .bashrc is executed for an interactive non-login shell

Use .bash_profile to run commands that should run only once, such as customizing the $PATH environment variable .

Put the commands that should run every time you launch a new shell in the .bashrc file. This include your aliases and functions , custom prompts, history customizations , and so on.

Typically, ~/.bash_profile contains lines like below that source the .bashrc file. This means each time you log in to the terminal, both files are read and executed.

if [ -f ~/.bashrc ]; then
	. ~/.bashrc
fi

Most Linux distributions are using ~/.profile instead of ~/.bash_profile. The ~/.profile file is read by all shells, while ~/.bash_profile only by Bash.

If any startup file is not present on your system, you can create it.

Conclusion

.bash_profile and .bashrc are files containing shell commands that are run when Bash is invoked. .bash_profile is read and executed on interactive login shells, while .bashrc on non-login shells.