Set environment variables on Mac OS X Lion
First, one thing to recognize about OS X is that it is built on Unix. This is where the .bash_profile comes in. When you start the Terminal app in OS X you get a bash shell by default. The bash shell comes from Unix and when it loads it runs the .bash_profile script. You can modify this script for your user to change your settings. This file is located at:
~/.bash_profile
Update for Mavericks
OS X Mavericks does not use the environment.plist - at least not for OS X windows applications. You can use the launchd configuration for windowed applications. The .bash_profile is still supported since that is part of the bash shell used in Terminal.
Lion and Mountain Lion Only
OS X windowed applications receive environment variables from the your environment.plist file. This is likely what you mean by the ".plist" file. This file is located at:
~/.MacOSX/environment.plist
If you make a change to your environment.plist file then OS X windows applications, including the Terminal app, will have those environment variables set. Any environment variable you set in your .bash_profile will only affect your bash shells.
Generally I only set variables in my .bash_profile file and don't change the .plist file (or launchd file on Mavericks). Most OS X windowed applications don't need any custom environment. Only when an application actually needs a specific environment variable do I change the environment.plist (or launchd file on Mavericks).
It sounds like what you want is to change the environment.plist file, rather than the .bash_profile.
One last thing, if you look for those files, I think you will not find them. If I recall correctly, they were not on my initial install of Lion.
Edit: Here are some instructions for creating a plist file.
- Open Xcode
- Select File -> New -> New File...
- Under Mac OS X select Resources
- Choose a plist file
- Follow the rest of the prompts
To edit the file, you can Control-click to get a menu and select Add Row. You then can add a key value pair. For environment variables, the key is the environment variable name and the value is the actual value for that environment variable.
Once the plist file is created you can open it with Xcode to modify it anytime you wish.
Your .profile or .bash_profile are simply files that are present in your "home" folder. If you open a Finder window and click your account name in the Favorites pane, you won't see them. If you open a Terminal window and type ls to list files you still won't see them. However, you can find them by using ls -a in the terminal. Or if you open your favorite text editor (say TextEdit since it comes with OS X) and do File->Open and then press Command+Shift+. and click on your account name (home folder) you will see them as well. If you do not see them, then you can create one in your favorite text editor.
Now, adding environment variables is relatively straightforward and remarkably similar to windows conceptually. In your .profile just add, one per line, the variable name and its value as follows:
export JAVA_HOME=/Library/Java/Home
export JRE_HOME=/Library/Java/Home
etc.
If you are modifying your "PATH" variable, be sure to include the system's default PATH that was already set for you:
export PATH=$PATH:/path/to/my/stuff
Now here is the quirky part, you can either open a new Terminal window to have the new variables take effect, or you will need to type .profile or .bash_profile to reload the file and have the contents be applied to your current Terminal's environment.
You can check that your changes took effect using the "set" command in your Terminal. Just type set (or set | more if you prefer a paginated list) and be sure what you added to the file is there.
As for adding environment variables to GUI apps, that is normally not necessary and I'd like to hear more about what you are specifically trying to do to better give you an answer for it.