When my work laptop was originally set up the short name was set to “paul kehrer”. This space tends to cause issues with poorly written applications, especially on the command line, so I set out to change it. Prior to Leopard this was a difficult task best accomplished with ChangeShortName, but with Leopard you can now do it without any third party utilities.

First you’ll need to create a secondary admin account and log into that. While you can directly change the short name of an account you are logged into, I wouldn’t recommend it. Next, open system preferences, go to More >