passwd : update user's auth tokens
[SYNOPSIS] passwd OPTION USER
OPTION
-d delete the password for the named account (root only)
also removes password lock if any
# passwd -d user
-l lock the password for the named account (root only)
# passwd -l user
-u unlock the password for the named account (root only)
-e expire the password for the named account (root only)
-x DAYS maximum password lifetime (root only)
# passwd -x 60 user
-n DAYS minimum password lifetime (root only)
# passwd -n 1 user
-w DAYS number of days warning users receives before password expiration (root only)
-i DAYS number of days after password expiration when an account becomes disabled (root only)
--stdin read new tokens from stdin (root only)
# echo password | passwd user --stdin
-S report password status on the named account (root only)
# passwd -S user
user PS 2009-09-12 0 99999 7 -1 (Password set, MD5 crypt.)
# What each field means
[Username]
[State : PS (Active); LK (password locked or not set)]
[Password last changed]
[Minimum password age (-n) = PASS_MIN_DAYS]
[Password Expiration (-x) = PASS_MAX_DAYS]
[Number of days warning before expiration (-w) = PASS_WARN_AGE]
[Number of days until the account expires and is disabled (-i)]