PASSWD(1) BSD Reference Manual PASSWD(1)
passwd - modify a user's password
passwd [-l] [-y] [-K] [user]
passwd changes the user's local, Kerberos, 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.
-K Forces the change to affect the Kerberos 5 database, even if the
user has a password in the local database. Once the password has
been verified, passwd communicates the new password information
to the Kerberos authenticating host.
This is the behavior if no flags are specified: if Kerberos is active
then passwd will talk to the Kerberos server (even if the user has an en-
try in the local database). If 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.
Which type of cipher is used to encrypt the password information depends
on the configuration in login.conf(5). It can be different for local
("localcipher") and YP ("ypcipher") passwords. If none is specified, then
blowfish with 6 rounds is used for local ("localcipher") and old is used
for YP ("ypcipher") by default.
/etc/login.conf configuration options
/etc/master.passwd user database
/etc/passwd a 6th Edition-style password file
/etc/passwd.XXXXXX temporary copy of the password file
/etc/ptmp lock file for the passwd database
Attempting 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). If passwd is interrupted
while trying to gain the lock the password changed 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.
chpass(1), kinit(1), login(1), login.conf(5), passwd(5), pwd_mkdb(8),
vipw(8)
Robert Morris and Ken Thompson, UNIX password security.
A passwd command appeared in Version 3 AT&T UNIX.
MirBSD #10-current July 24, 1991 1