NAME

passwd − change login password

SYNOPSIS

passwd [ −f filename ] [ username ]

DESCRIPTION

This command installs or changes a password associated with the user’s username (your own by default). 

Passwd prompts for the old password and then for the new one.  You must type the new password twice to forestall mistakes. 

A password is truncated if longer than 8 characters, but passwd doesn’t complain if you enter a longer password.  If a password combines upper- and lowercase characters, it should be at least five characters long; if it is in monocase, it should be at least six characters long.  A shorter password compromises your security. 

Only the owner of the name or the superuser may change a password; the owner must prove knowledge of the old password. 

Use yppasswd to change your password in the network Yellow Pages.  This will not affect either your local password or your password on any remote machines on which you have accounts. 

OPTIONS

−fTreat filename as the password file. 

FILES

/etc/passwd
/etc/yp/passwd

SEE ALSO

login(1), passwd(5), yppasswd(1), crypt(3)
Robert Morris and Ken Thompson, UNIX password security

BUGS

Password file information should be kept in a different data structure allowing indexed access; dbm(3X) would probably be suitable.

passwd changes a local password, but not a password in the network Yellow Pages.  Refer to yppasswd(1) for information on how to change a Yellow Pages password. 

4BSD