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passwd(1) General Commands Manual passwd(1) NAME passwd, chfn, chsh - Changes password file information SYNOPSIS passwd [-f|-s] [username] chfn [username] chsh [username] This security-sensitive command uses the SIA (Security Integration Ar- chitecture) routine as an interface to the security mechanisms. See the matrix.conf(4) reference page for more information. OPTIONS Invokes the chfn command when given with the passwd command. Invokes the chsh command when given with the passwd command. DESCRIPTION The passwd command changes (or installs) the password associated with your username (by default) or the specified username. The chfn command changes the finger information in the GECOS field as- sociated with your username or the specified username. GECOS is an ob- solete term, but refers to the finger information field of the passwd structure as defined in the <pwd.h> file and the finger information field of the /etc/passwd file as described in the passwd(4) reference page. The information in the GECOS field has been formalized by POSIX and is a comma separated list containing the user's full name, office phone, office number, and home phone number. The chsh command changes the login shell of your username or of the specified username. When using the passwd command to alter a password, the command prompts for the current password and then for the new one. The caller must supply both. The new password must be typed twice to forestall mis- takes. Each password must have at least six characters and can include digits, symbols, and the letters of your alphabet. It is strongly suggested that you include unusual punctuation, control characters, or digits in your password. Use of only lowercase letters is discouraged. If you enter more than eight characters when creating a password, the passwd command ignores any characters after the eighth. When altering the GECOS information field, the chfn command displays the current information, broken into fields, as interpreted by the fin- ger program, among others, and prompts for new values. These fields in- clude a user's proper name, office room number, office phone number, and home phone number. Included in each prompt is a default value, which is enclosed in [ ] (brackets). The default value is accepted simply by pressing <Return>. To enter a blank field, the word none can be entered. The chfn command allows phone numbers to be entered with or without dashes. It is a good idea to run finger after changing the GECOS in- formation to make sure everything is set up properly. A superuser can change anyone's GECOS information; other users can only change their own. When altering a login shell, the chsh command displays the current lo- gin shell and then prompts for the new one. The new login shell must be one of the approved shells listed in the /etc/shells file unless you have superuser privileges. If the /etc/shells file does not exist, the only shells that can be specified are /usr/bin/sh and /usr/bin/csh. Note that if you specify an abbreviated shell name, the command chooses the first entry in the /etc/shells file that matches the shell abbrevi- ation. For example, if you specify ksh, and both the /bin/ksh and /usr/bin/ksh shells are included in the /etc/shells file, the shell is changed to the shell that is specified first. A superuser can change anyone's login shell; normal users can only change their own login shell. Security Note When you use the passwd command, with enhanced security installed, the system prompts for the existing password, and begins a password solici- tation dialog that depends on the options for password generation the administrator has enabled for your account. There are four possible options: A pronounceable password made up of meaningless syllables. An unpronounceable password made up of random characters from the charac- ter set. An unpronounceable password made up of random letters from the alphabet. A user specified password, which is subject to length and triviality restrictions. A maximum length is specified for all user passwords. The minimum password length depends on several parameters set in the authentication databases. The system requires a minimum time to elapse before you can change your password. This stops you from reusing an old password too soon. A password expires after a period of time known as the expiration time. The system warns you when the expiration time is drawing near. A password dies after a period of time known as the password lifetime. After the lifetime passes, your account is locked until the administra- tor reenables it. After unlocking, you must change your password again before you can use your account. When you successfully type your old password, the system prints the last successful and unsuccessful password change times. Make sure that these times are accurate; use them to detect attempted password changes by an unauthorized user. You can change your own password if the administrator has enabled any of the password generation options for your account. Using the passwd command to reset a user's password does not unlock the user's account if the account is locked for a reason other than an ex- pired password. If a password longer than 8 characters was entered under base security and then enhanced security is installed, you must use only the first 8 characters of the original password. This is because base security only used the first 8 characters of the password and the enhanced/ex- tended password is created from the base password. See the Security manual for detailed instructions on changing your password. EXAMPLES To change your password, enter: passwd You are prompted for your old password (if it exists). You are then prompted twice for the new password. To change the office number and building values in your GECOS information, enter: chfn Your current GECOS values are displayed. Follow the instruc- tions and change your office number. For example, enter: Name [Huan Kim]: Room Number [3A-41]: 4A-43 Office Phone [3-1234]: Home Phone [555-1234]: FILES Contains user information. The list of approved shells. SEE ALSO Commands: finger(1), login(1), vipw(8) Files: matrix.conf(4), passwd(4) Security passwd(1)