usermod - modify a user account
[SYNOPSIS] usermod OPTION USER
option
-d new home directory for the user account
-g force use GROUP as new primary group
-G new list of supplementary GROUPS
-a --append
append the user to the supplemental GROUPS
mentioned by the -G option without removing
the user from other groups
-s new login shell for the user account
-u new UID for the user account
-L lock the user account
-U unlock the user account