NAME

passwd − change login password

SYNOPSIS

passwd [-f file] [name]

DESCRIPTION

passwd changes or installs a password associated with the login name. If name is omitted, passwd uses getlogin() to determine the invoking user’s user name (see getlogin(3C)). An alternate password file can be chosen with the -f option.  The user must have read and write permission for the file given with the -f option.  The default password file is /etc/passwd. 

Ordinary users can change only the password corresponding to their login name.

passwd prompts ordinary users for their old password, if any.  It then prompts for the new password twice.  The first time the new password is entered passwd checks to see if the old password has “aged” sufficiently.  If “aging” is insufficient, the new password is rejected and passwd terminates; see passwd(4).

Assuming “aging” is sufficient, a check is made to ensure that the new password meets construction requirements.  When the new password is entered a second time, the two copies of the new password are compared.  If the two copies differ, passwd repeats the cycle of prompting for the new password, at most twice. 

Passwords must be constructed to meet the following requirements:

• Each password must have at least six characters.  Only the first eight characters are significant. 

• Characters must be from the 7-bit USASCII character set; letters from the English alphabet. 

• Each password must contain at least two alphabetic characters and at least one numeric or special character.  In this case, “alphabetic” means uppercase and lowercase letters. 

• Each password must differ from the user’s login name and any reverse or circular shift of that login name. For comparison purposes, an uppercase letter and its corresponding lowercase equivalent are are treated as identical.

• New passwords must differ from the old one by at least three characters.  For comparison purposes, an uppercase letter and its corresponding lowercase equivalent are are treated as identical. 

A user whose effective user ID is zero is called a super-user; see id(1), and su(1). Super-users can change any password; hence, passwd does not prompt super-users for the old password.  Super-users are not forced to comply with password aging and password construction requirements.  A super-user can create a null password by entering a carriage return in response to the prompt for a new password. 

EXTERNAL INFLUENCES

International Code Set Support

Characters from single-byte character code sets are supported in passwords. 

FILES

/etc/passwd

SEE ALSO

id(1), login(1), su(1), crypt(3C), passwd(4). 

STANDARDS CONFORMANCE

passwd: SVID2, XPG2

Hewlett-Packard Company  —  HP-UX Release 9.0: August 1992