passwd [–u userid]
passwd changes the login password or password phrase for the user ID specified. If userid is omitted, the login name associated with the current terminal is used. You are prompted for the new password or password phrase, which may be truncated to the length defined as the maximum length for the passwords.
Users can change the password or password phrase for another user if they know the user ID and current password or password phrase.
passwd
You
will be prompted for the old password or password phrase and the new
password or password phrase.passwd -u steve
You
will be prompted for the old password or password phrase and the new
password or password phrase.