man passwd看到几个参数

OPTIONS
       -k     The  option, -k, is used to indicate that the update should only
              be for  expired  authentication  tokens  (passwords);  the  user
              wishes to keep their non-expired tokens as before.

       -l     This  option  is  used  to  lock the specified aclearcase/" target="_blank" >ccount and it is
              available to root only. The locking is  performed  by  rendering
              the  encrypted password into an invalid string (by prefixing the
              encrypted string with an !).

       --stdin
              This option is used to indicate that passwd should read the  new
              password from standard input, which can be a pipe.

       -u     This  is  the  reverse  of  the  -l  option - it will unlock the
              account password by removing the ! prefix. This option is avail-
              able  to  root  only.  By default passwd will refuse to create a
              passwordless account (it will not unlock  an  account  that  has
              only  "!" as a password). The force option -f will override this
              protection.

       -d     This is a quick way to disable a password  for  an  account.  It
              will set the named account passwordless. Available to root only.

       -n     This will set the minimum password lifetime,  in  days,  if  the
              userâ

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