term% cat index.txt PASSWD(1) General Commands Manual 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 suf‐
ficiently rich alphabet and at least six characters long if monocase.
These rules are relaxed if you are insistent 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 re‐
sponse 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 di‐
rectory, 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
BUGS
The password file information should be kept in a different data struc‐
ture allowing indexed access.
PASSWD(1)