Where to find the .bashrc file on Mac OS X Snow Leopard and Lion?

Regarding the problem with .bashrc above:

On most systems, ~/.bashrc is only used when starting an interactive non-login shell. However, when you start up a new shell it is often an interactive login shell. Since this is a login shell, the .bashrc is ignored. To keep the environment consistent between non-login and login shells, you must source the .bashrc from your .profile or your .bash_profile.

See the Bash Reference Manual, section 6.2 Bash Startup Files

Invoked as an interactive login shell, or with --login

When Bash is invoked as an interactive login shell, or as a non-interactive shell with the --login option, it first reads and executes commands from the file /etc/profile, if that file exists. After reading that file, it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile, in that order, and reads and executes commands from the first one that exists and is readable.

Invoked as an interactive non-login shell

When an interactive shell that is not a login shell is started, Bash reads and executes commands from ~/.bashrc, if that file exists.

So, typically, your ~/.bash_profile contains the line

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

after (or before) any login-specific initializations.

On my Mac (Running Leopard), there was no line to source ~/.bashrc. I had to add this functionality on my own.

On some systems and other OSes, .bashrc is sourced from the global /etc/profile or /etc/bash_profile , or is done using the template files from /etc/skel.

To be honest the distinction between .bashrc and .bash_profile is not well understood by the community. When many developers say "Add this to your .bashrc", what they really mean is "Add this to your .bash_profile". They want the functionality to be added to your login shell (which is .bash_profile), not to your non-login shell. In reality, it doesn't usually matter and placing configuration in .bashrc is acceptable.

So turns out that on Mac OS X Snow Leopard as well as Mac OS X Lion, the file that's loaded is called .profile, not .bashrc.

What you want to do is create a file in ~/.profile and call it .profile (if it doesn't already exists).

Put whatever information you needed to load with each instance of bash there (Thanks, thepurplepixel).

A couple of side notes:

1. The period in front of the file marks it as invisible to Finder and the ls command by default. To list invisible files using the ls command from Terminal, use the -a as a parameter as such: ls -a
2. The ~ symbol stands for /Users/YourUserName where YourUserName is your username's shortname.

Edit: Chris Page notes (correctly) that whatever you place in a .profile file will apply to whatever shell you're using (i.e. zhs, bash, et cetera). If you want the contents to affect only the bash shell, place the contents in a .bash_profile file instead of a .profile file.

You have to make your own .bashrc. You can simply use a text editor to make a file called .bashrc (no extension) with the contents you want and save it in your home directory (/Users/YourUserName/).