Customizing Your Terminal: .bash_profile and .bashrc files

Custom terminal settings only “stick” when they’re placed in the right startup files—specifically the dotfiles in a user’s home directory: .bash_profile and .bashrc. Typing changes like PS1=... can update the prompt immediately, but they vanish when the terminal is closed and reopened. The practical fix is to edit these files so the shell applies preferences every time a new session starts, including when connecting remotely via SSH.

The workflow starts by locating the dotfiles (ls won’t show them unless dotfiles are included). If .bash_profile or .bashrc don’t exist, they can be created. To demonstrate the difference between the two, the transcript temporarily moves the existing .bash_profile and .bashrc out of the way, confirming that previously added customizations—like prompt color changes and Git-related display—no longer appear. Recreating the files then makes it clear which one runs under which circumstances.

On macOS, opening a new terminal session triggers a login shell, which runs commands from .bash_profile. In contrast, .bashrc does not run during that initial login-shell startup. However, .bashrc does run when starting a non-login shell (or a subshell). The transcript shows this by adding echo statements to each file: reopening the terminal prints the .bash_profile message but not the .bashrc message; running bash to spawn a subshell prints the .bashrc message.

Because login shells and non-login shells behave differently, many users end up duplicating configuration. A cleaner approach is to centralize customizations in .bashrc and have .bash_profile delegate to it. The method is a small conditional in .bash_profile that checks whether .bashrc exists and then sources it (i.e., executes its contents in the current shell). In effect, every time a login shell starts, .bash_profile runs first, then immediately loads .bashrc; and when a subshell starts, .bashrc runs directly. That structure ensures the same prompt and other settings apply consistently across shell types.

Once this wiring is in place, changes made to .bashrc—such as setting PS1 to a custom prompt—persist across both fresh terminal launches and subshells. The result is a single “home” for terminal customization, setting up the foundation for later improvements like aliases, Git branch prompts, Git autocompletion, and environment variable exports (including PATH adjustments). The key takeaway is that correct file placement and sourcing logic determine whether terminal customization is temporary tinkering or reliable daily workflow.