I\'m on OSX and I need to put something like this, alias blah=\"/usr/bin/blah\" in a config file but I don\'t know where the config file is.
You can add an alias or a function in your startup script file. Usually this is .bashrc, .bash_login or .profile file in your home directory.
Since these files are hidden you will have to do an ls -a to list them. If you don't have one you can create one.
If I remember correctly, when I had bought my Mac, the .bash_login file wasn't there. I had to create it for myself so that I could put prompt info, alias, functions, etc. in it.
Here are the steps if you would like to create one:
cd ~/ to go to your home foldertouch .bash_profile to create your new file..bash_profile with your favorite editor (or you can just type open -e .bash_profile to open it in TextEdit.. .bash_profile to reload .bash_profile and update any alias you add.