Summary: How to change the UID and or GID on Red Hat.
Date: Around 2015
Refactor: 21 February 2025: Checked links and formatting.

Follow these commands to change the user's uid and primary group gid.

First check the users UID and GID, as well as the GIDs name like this:

cat /etc/passwd | grep <username>
id <username>

This will give you all the output you need. Now use these commands to change the UIDs and ownership of the files:

usermod -u <NEWUID> <LOGIN>
groupmod -g <NEWGID> <GROUP>
find / -user <OLDUID> -exec chown -h <NEWUID> {} \;
find / -group <OLDGID> -exec chgrp -h <NEWGID> {} \;

Note that on old versions you might also have to do this: usermod -g <NEWGID> <LOGIN>. On new versions this is not longer required.

Note that if you have NFS shares which also holds these uid/gid you need to follow the same procedure there if you have root squash enabled. You will get permission denied messages when you run into this.