PASSWD(1) PASSWD(1)
NAME
passwd - change login password
SYNOPSIS
passwd [ -an ] [ name ]
DESCRIPTION
This command changes (or installs) a password associated
with the user name (your own name by default).
The program prompts for the old password and then for the
new one. The caller must supply both. The new password
must be typed twice, to forestall mistakes.
New passwords must be at least four characters long if they
use a sufficiently rich alphabet and at least six characters
long if monocase. These rules are relaxed if you are insis-
tent enough.
Only the owner of the name or the super-user may change a
password; the owner must prove he knows the old password.
If the -a option is given, passwd prompts for new values of
certain fields of the password file entry.
The super-user may use the -n option to install new users.
The prompts are self-explanatory, and most of the defaults
obvious. A null response to the ``UID:'' prompt assigns a
numeric userid one greater than the largest one previously
in /etc/passwd. A null response to the ``Directory:'' prompt
assigns the user a home directory in /usr. If the first
character of the response to this prompt is an asterisk, the
remaining characters are taken as the name of the new user's
home directory, and a symbolic link to this directory is
placed in /usr. A user can be assigned a directory with a
name of the form /dir/username by replying *dir.
A new user's home directory starts with a file named
.profile. This file is a copy of /etc/stdprofile with \N
replaced by the user's name, and \D replaced by the name of
the user's home directory.
FILES
/etc/passwd
/etc/stdprofile
SEE ALSO
passwd(5), crypt(3)
Robert Morris and Ken Thompson, UNIX password security
PASSWD(1) PASSWD(1)
BUGS
The password file information should be kept in a different
data structure allowing indexed access.