Network, Computer and Programming Resources

Linux top 50 cmd - Passwd

For the normal user (non-superuser), no arguments are used with the passwd command. The command will ask the user for the old password. Following this, the command will ask for the new password twice, to make sure it was typed correctly. The new password must be at least six characters long and must contain at least one character that is either uppercase or a nonletter. Also, the new password cannot be the same password as the one being replaced, nor can it match the user's ID (account name). If the command is run by the superuser, it can be followed by either one or two arguments. If the command is followed by a single user's ID, then the superuser can change that user's password. The superuser is not bound by any of the restrictions imposed on the user. If there is an argument after the single user's ID, then that argument becomes that user's new password.