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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
Architecture) routine as an interface to the security mechanisms. See the
matrix.conf(4) reference page for more information.
OPTIONS
-f Invokes the chfn command when given with the passwd command.
-s 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
associated with your username or the specified username. GECOS is an
obsolete 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 mistakes.
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 finger
program, among others, and prompts for new values. These fields include 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 information 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 login
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 abbreviation.
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
solicitation dialog that depends on the options for password
generation the administrator has enabled for your account. There are
four possible options:
Random syllables
A pronounceable password made up of meaningless syllables.
Random characters
An unpronounceable password made up of random characters from the
character set.
Random letters
An unpronounceable password made up of random letters from the
alphabet.
User supplied
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
administrator 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
expired 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/extended password is created from the base password.
See the Security manual for detailed instructions on changing your
password.
EXAMPLES
1. 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.
2. To change the office number and building values in your GECOS
information, enter:
chfn
Your current GECOS values are displayed. Follow the instructions 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
/etc/passwd
Contains user information.
/etc/shells
The list of approved shells.
SEE ALSO
Commands: finger(1), login(1), vipw(8)
Files: matrix.conf(4), passwd(4)
Security