PASSWD(1) Linux Programmer's Manual PASSWD(1)
NAME
passwd(1,5) - change password
SYNOPSIS
passwd(1,5) [ -o ] [ -q ] [ -v ] [ name [ password ]]
passwd(1,5) -f [ arguments to chfn ]
passwd(1,5) -s [ arguments to chsh ]
DESCRIPTION
Without arguments passwd(1,5) will change the password for the current user.
First the user is asked for the old password, then prompted twice for
the new password in(1,8) order to catch typing errors.
The one and two argument forms may only be used by the superuser. Using
the one argument form, the superuser may change the password for that
user. The superuser is not asked for the users(1,5) old password, but the
rules for proper passwords are also applied unless the -o option is
used. The superuser may have legitimate reasons to choose a non-confor-
mant password.
The two argument form gives the user the password stated as the second
argument. Note that this password will be visible to people doing `ps'
or so. Avoid this form.
Giving an empty string(3,n) as the second argument erases the password for
the user, but only in(1,8) combination with the -o option.
Password changes may get logged using the syslog(2,3,5,3 Sys::Syslog)(3) facility, depending
on compile-time defines (on by default). If so, every change will be
logged at a low level as auth.notice, except for changing the root
password with will be logged with auth.warning.
OPTIONS
-f, --fullname
Change the user's full name (the GECOS field of the passwd(1,5)
entry). Invokes /usr/bin/chfn with the non-option command line
arguments.
-o, --force
Turn off simplicity checks on the new password. This option may
only be used by the super user. This is intend to allow simple
initial passwords given by the superuser.
-s, --shell
Change the user's shell by invoking /usr/bin/chsh with the non-
option command line arguments.
-q, --quiet, --silent
In this mode passwd(1,5) won't tell that the passwd(1,5) get's changed.
-v, -V, --version
Prints version(1,3,5) information and exits.
PASSWORD RULES
The new password must fulfill these rules:
o be at least six characters long;
o must not be equal to the old password;
o must contain characters out of at least two of the following
classes: upper and lower case letters, digits and non alphanu-
meric characters;
o must not match neither the username nor any word of the real-
name, neither in(1,8) normal nor in(1,8) reverse order, neither at the
beginning nor at the end.
BUGS
If you change your mind there is no escaping from this program. It
will insist on a new password until killed from another terminal.
(This is caused by a bug in(1,8) getpass(3): it ignores signals.)
FILES
/etc/passwd(1,5)
The password file.
SEE ALSO
chsh(1), chfn(1), syslog(2,3,5,3 Sys::Syslog)(3), syslog.conf(5), passwd(1,5)(8).
AUTHOR
Peter Orbaek (poe@daimi.aau.dk).
Martin Schulze (joey@infodrom.north.de) with extensive rewriting and
improving done.
Util-linux 2.6 11 November 1996 PASSWD(1)