passwd(1) passwd(1)
NAME
passwd - change login password
SYNOPSIS
passwd [name]
DESCRIPTION
This command changes (or installs) a password associated
with the login name.
Ordinary users may change only the password which
corresponds 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 are not
identical, the cycle of prompting for the new password is
repeated for at most two more times.
Passwords must meet the following requirements:
Each password must have at least six characters. Only
the first eight characters are significant.
Each password must contain at least two alphabetic
characters (uppercase or lowercase) and at least one
numeric or special character.
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 letter are equivalent.
New passwords must differ from the old by at least
three characters. For comparison purposes, an
uppercase letter and its corresponding lowercase letter
are equivalent.
One whose effective user ID is zero is called a super-user;
see id(1), and su(1). Super-users may 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
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passwd(1) passwd(1)
return in response to the prompt for a new password.
EXAMPLE
passwd
will give the response
Changing password for <username>
and will then prompt for your present password and for the
new password (twice).
FILES
/bin/passwd
/etc/passwd
SEE ALSO
login(1), id(1), su(1), crypt(3C), passwd(4).
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