Not being able to edit user's info in linux

I have managed to write this code. It runs, but no change was made to the user's info. It seems like usermod isn't working. What I am wanting to do is, to be able to edit existing user's info in the system? printf "\nEnter user name to edit: " read -r usermod [ -n $usermod ] && usermod $usermod unset usermod echo " A user name has been edited"