usermod — Modify a user account
The usermod command modifies the system account files to reflect the changes that are specified, like Home dir, password, etc. on the command line
# usermod -d /home2/usr1 usr1 — Create the new home Dir for usr1 in /home2 & Move old Dir contents to this Dir.
# usermod -e 2005-04-30 usr1 — From 30/4/2005 the usr1 acc will be disabled.
# usermod -f 6 usr1 — After passwd expires, system will allow the user to login for 6 days with a warning to change his passwd.
# usermod -g prof usr1 — Set usr1’s initial group as prof.
# usermod -p $1$d8 usr1 — Set the new passwd for the usr1
# usermod -s /bin/bash usr1 — Set Bash as the default login shell for the usr1.
# usermod -L usr1 — Lock a user’s password.
# usermod -U usr1 — Unlock a user’s password.
Read: man usermod