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.
On OS X you want to use ~/.bash_profile. This is because by default Terminal.app opens a login shell for each new window.
See more about the different configuration files and when they are used here: What's the difference between .bashrc, .bash_profile, and .environment?
and in relation to OSX here: About .bash_profile, .bashrc, and where should alias be written in?