NAME
passwd
—
modify a user's password
SYNOPSIS
passwd |
[user] |
DESCRIPTION
passwd
changes the user's password. If no
user is specified, the user's login name is used (see
logname(1)). First, the user is prompted for their current password.
If the current password is correctly typed, a new password is requested. The
new password must be entered twice to avoid typing errors.
The new password should be at least six characters long and not
purely alphabetic. Its total length must be less than
_PASSWORD_LEN
(currently 128 characters). A mixture
of both lower and uppercase letters, numbers, and meta-characters is
encouraged.
The quality of the password can be enforced by specifying an external checking program via the “passwordcheck” variable in login.conf(5).
The superuser is not required to provide a user's current password if only the local password is modified.
Password encryption parameters depend on the configuration of the “localcipher” capability in login.conf(5). If none is specified, then blowfish with 8 rounds is used.
FILES
- /etc/login.conf
- configuration options
- /etc/master.passwd
- user database
- /etc/passwd
- user database, with confidential information removed
- /etc/passwd.XXXXXX
- temporary copy of the password file
- /etc/ptmp
- lock file for the passwd database
DIAGNOSTICS
- Attempting to lock password file, please wait or press ^C to abort
-
The password file is currently locked by another process;
passwd
will keep trying to lock the password file until it succeeds or you hit the interrupt character (control-C by default). Ifpasswd
is interrupted while trying to gain the lock the password change will be lost.If the process holding the lock was prematurely terminated the lock file may be stale and
passwd
will wait forever trying to lock the password file. To determine whether a live process is actually holding the lock, the admin may run the following:$ fstat /etc/ptmp
If no process is listed, it is safe to remove the /etc/ptmp file to clear the error.
SEE ALSO
chpass(1), encrypt(1), logname(1), login.conf(5), passwd(5), pwd_mkdb(8), vipw(8)
Robert Morris and Ken Thompson, Password security: a case history, Communications of the ACM, Issue 11, Volume 22, 594–597, Nov. 1979.
HISTORY
A passwd
command appeared in
Version 3 AT&T UNIX.