When I upgraded to Mountain Lion everything seemed fairly smooth sailing until I tried to clone a repository in git. As it turns out there are a couple steps you must take to get rid of the dreaded -bash: git: command not found when you enter git commands in terminal.
Step 1. Open up XCode (or if you don’t have it yet, download it from the Mac App Store here.
Step 2. Press ? , (The command key and comma) to open up XCode’s Preferences (pictured below). Under the downloads tab you’ll see Command Line Tools in the last row.
Step 3. Click the rounded Install button next to Command Line Tools and wait for the install to complete. (You’ll see a blue progress bar and then it will say Installed.)
Step 4. Type git into the command line and you’ll see your normal response again.