Change user id and group id of user

Last Modified: March 1, 2020

If you run into an issue where you need to change the user id (uid) and group id (gid) of a user (<user>). Assume you want to change uid:gid from 1001:1001 (<old_uid>:<old_gid>) to 1000:1000 (<new_uid>:<new_gid>).

Steps by step guide

Login using a different user. If need root user: ssh root@<hostname>.
Kill all the process of user. Find all process belonging to <user> using ps:
```
ps aux | grep <user>
```
Change uid of <user>:
```
usermod -u <new_uid> <user>
```
Change gid of user:
```
groupmod -g <new_gid> <user>
```

Change ownership of all files from <old_uid>:<old_gid> to <new_uid>:<new_gid>:

find /parent/path/ \( -uid <old_uid> -o -gid <old_gid> \) \
  -exec chown <new_uid>:<new_gid> {} \;

Example:

find /home/lento \( -uid 1001 -o -gid 1001 \) \
  -exec chown 1000:1000 {} \;