Linux Shells by Example

passwd—changes the login password and password attributes

passwd [ name ]
passwd [ –d | –l ] [ –f ] [ –n min ] [ –w warn ][ –x max ] name
passwd –s [ –a ]
passwd –s [ name ]

The passwd command changes the password or lists password attributes associated with the user's login name. Additionally, privileged users may use passwd to install or change passwords and attributes associated with any login name.