Shell Programming and Scripting

Yes.
You are right - the find command is reversible.

Thanks. Haven't tried this one yet.. Being overly cautious so I wanted to ask- Is this the cause of the login issue I was having when I changed the uid before or could it be something else? Many posts I've seen about changing the uid just show how to change the uid without any mention of this issue I'm having. And if this is the issue, do you know the specific files or directories within this users home directory that are the ones responsible for the login issue? If its just a few, I could perhaps just change those to test the theory.

Hi Stellaman,

Your suggested methodology for changing the user ID and file ownership is the correct way to make the change. Bringing the User ID's and the Group ID's into alignment will probably be required, depending on what the user population is on the estate you may have to repeat this exercise for a number of users. Now would probably be a good time to plan a system for the management/alignment of the User ID's and Group ID's over the whole estate.

This is a common issue in the world of larger estates, it is frequently down to organic growth - where no or poor forward planning is in place. Large enterprises tend to have management tools in place, where user ID's can be correctly managed - this tends to happen after the problem has been encountered.

Regards

Gull04

OK, I ran the commands and the user was able to log in successfully after the uid change. He also looked around his files on the NAS and Thanks! Though I now noticed that while his uid matches between the two machines, the group IDs do not match. Is this a problem?

Hi Stellaman;

The group ID's are not so much of a problem - however it is best practice to keep them aligned as some users may depend on group permissions for access to files/programs.

If you check the /etc/group file on each of the system, you should be able to bring both accounts into alignment. This can be done in the same manner that you aligned the user ID's, but you should check the group memberships as unlike user ID's many users can be members of groups.

Regards

Gull04

Yes, even if it currently might not matter, it is better to have the GIDs in sync as well.
Analogue to the

Code:

usermod -u newuid username
find /home/username -user olduid -exec chown -h newuid {} +

you run

Code:

groupmod -g newgid groupname # changes /etc/group and perhaps referring entries in /etc/passwd
usermod -g newgid username # if not done by the previous groupmod
find /home/username -group oldgid -exec chgrp -h newgid {} +

The user must logout/login on the target system otherwise she would continue with the old GID.

This is true for locally attached disk or SAN based file systems, but hopefully not for NAS based ones.

As shared directory wouldn't make sense if not shareable.

I agree there is a risk of file corruption (but not file system corruption) if multiple clients access the same file at the same time, but this risk also exists when multiple processes do the same on a single host.