You can actually change the short name of a user through the NetInfo Manager utility. The thing about creating a new account, and then deleting the old account is that your old files won't have the correct permissions assigned to them, so you'll either have to run Disk Utility to repair your permissions after the change, or you may risk not having the correct permissions and causing problems (not to mention security breaches). I currently am using a user on my Mac at work which originally had a different user name, and I have had absolutely zero problems after doing the change.
I'd actually recommend going through this series of steps if you just want to change your short user name -- no Terminal experience required (or even necessary), and you'll have the benefit of a new short user name and preserved permissions.
NOTE: You will need to be logged in as an administrator user (or have access to an administrator log/pass) in order to perform this change. I would also
highly recommend quitting all other applications, to avoid saving data in your existing home folder which is soon to become your non-existing home folder.
Here are the steps to accomplishing this change:
1. Open up NetInfo Manager, located in /Applications/Utilities .
2. When the NetInfo Manager window first opens on startup, "/" should be selected in the first column. Select "users" in the second column.
3. Now, locate and select your current short user name. Mine was originally "samuil".
At this point, we have a bit of a problem. When changing your info, you're going to need to change the actual location of your home directory first. This shouldn't cause any problem even if you're running under the current user. The next few steps will show how to do this.
4. Open up the directory /Users in the Finder.
5. Deselect all user folders, and then open the Get Info window. This should get info on the Users folder.
6. Reveal the "Ownership & Permissions" pane.
Note the current ownership permissions. My Users folder ownership/permissions settings are as follows, and as far as I know, are correct.
PHP:
Owner: system
Access: Read & Write
Group: wheel
Access: Read & Write
Others: Read only
If the correct permissions are different, let me know.
7. Click the lock in the Ownership & Permissions pane, and then change the owner from "system" to your current short user name (in my example, this was "samuil"). You will now be prompted for an administrator password, which is required to continue.
8. Switch to the /Users folder window in the Finder. Click your home folder once to select it, press Enter to begin renaming it. (Your current home folder should NOT have a generic folder icon -- the icon should look like a house.)
9. Change the name of your current user folder to
your desired short name, *NOT* your full name (the correct new short user name, in my example, is "simmy"). Press Enter again to confirm the folder name change.
10. Switch to the Get Info window on the /Users folder, and reset the permissions to what they were. That is, change the owner back to system, and then click the lock to lock it.
11. Now, switch to the NetInfo Manager application. Click the lock at the bottom of the window -- you'll be prompted for your administrator password.
12. In the bottom pane where it lists the properties and their associated values for your current user, change all instances of your old short user name to your new short user name. For example, I changed all instances of "samuil" to "simmy".
I see a total of 6 values that need to be changed: "_writers_hint", "_writers_passwd", "name", "_writers_tim_password", "_writers_picture", and "home". For the "home" value, do NOT change it to just say your short user name -- you need it to say "/Users/newshortusername" where "newshortusername" is your new short user name, obviously.
The values that I listed above vary from system to system, so they may not all be there. If they aren't, don't worry about adding them -- just change the ones that are there that need to be changed.
13. Click the lock at the bottom of the NetInfo Manager window, and then press Command-S or choose "Save Changes" from the Domain menu to confirm your changes.
14. Log out, and log in.
Your old short user name will no longer be valid, but your new short user name and old full name will still work. The same password you used under your old short user name will also work -- the password has not changed. Note that if you do not log out, a new home directory under your old user name may be created in the Users folder even though there is no longer a user associated with that folder. So once you perform the above steps, it is
highly recommended that you immediately log out to prevent any future problems.
That's it! Your correct permissions will be preserved, because UNIX actually uses the user ID (the "uid" field in NetInfo Manager) to assign permissions, not the short user name. So changing the short user name won't affect your permissions, whereas deleting a user and then creating a new one will (because the new one will probably have a new user ID).
Hope that helps!
