# groupmod -g 1510 testgroup1
# usermod -u 1510 testuser1

# chgrp -R testgroup1 /home/testuser1

# chown testuser1:testgroup1    FILE
# chown testuser1:testgroup1 -R  DIRECTORY

# find / -uid 1000 -print0 | xargs -0 chown testuser1
# find / -gid 1000 -print0 | xargs -0 chgrp testgroup1

# id testuser1
# ls -la /home/testuser1
# find / -gid 1510 -print

Linux Commands Cheat Sheet