passwd[options] [user]
Create or change a password associated with a user name.
Only the owner or a privileged user may change a password. Owners
need not specify their user name.
Display password information:
user name.
Password status (NP for no password, PS for password, LK for locked).
The last time the password was changed (in mm/dd/yy format).
Number of days that must pass before user can rechange
the password.
Number of days before the password expires.
Number of days prior to expiration that user is warned
of impending expiration.
Use with -s to display password information for all users.
user should not be supplied.
Delete password; user is no longer prompted for one.
Force expiration of user's password; user must change
password at next login.
Lock user's password; mutually exclusive with -d.
Set item 4 of user's password information. Usually used with -x.
Set item 6 for user.
Set item 5 for user. Use -1 to disable password
aging, 0 to force expiration like -f.