NAME
passwd
—
modify a user's password
SYNOPSIS
passwd |
[-l | -y ]
[user] |
DESCRIPTION
passwd
changes the user's local or YP
password. 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 options are as follows:
-l
- Causes the password to be updated only in the local password file. When changing only the local password, pwd_mkdb(8) is used to update the password databases.
-y
- Forces the YP password database entry to be changed, even if the user has an entry in the local database. The rpc.yppasswdd(8) daemon should be running on the YP master server.
If no flags are specified and the password is not in the local password database, then an attempt is made to use the YP database.
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), login(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.