redhat man page for pwck

PWCK(1) 						      General Commands Manual							   PWCK(1)

NAME
       pwck - verify integrity of password files

SYNOPSIS
       pwck [-sr] [passwd shadow]

DESCRIPTION
       pwck  verifies  the  integrity of the system authentication information.  All entries in the /etc/passwd and /etc/shadow are checked to see
       that the entry has the proper format and valid data in each field.  The user is prompted to delete entries that are improperly formatted or
       which have other incorrectable errors.

       Checks are made to verify that each entry has

	    - the correct number of fields
	    - a unique user name
	    - a valid user and group identifier
	    - a valid primary group
	    - a valid home directory
	    - a valid login shell

       The  checks  for  correct  number  of fields and unique user name are fatal.  If the entry has the wrong number of fields, the user will be
       prompted to delete the entire line.  If the user does not answer affirmatively, all further checks are bypassed.  An entry  with  a  dupli-
       cated  user  name  is  prompted	for  deletion,	but the remaining checks will still be made.  All other errors are warning and the user is
       encouraged to run the usermod command to correct the error.

       The commands which operate on the /etc/passwd file are not able to alter corrupted or duplicated entries.  pwck should  be  used  in  those
       circumstances to remove the offending entry.

OPTIONS
       By default, pwck operates on the files /etc/passwd and /etc/shadow.  The user may select alternate files with the passwd and shadow parame-
       ters.  Additionally, the user may execute the command in read-only mode by specifying the -r flag.  This  causes  all  questions  regarding
       changes	to  be answered no without user intervention.  pwck can also sort entries in /etc/passwd and /etc/shadow by UID. To run it in sort
       mode pass it -s flag. No checks are performed then, it just sorts.

FILES
       /etc/passwd - user account information
       /etc/shadow - encrypted password information
       /etc/group - group information

SEE ALSO
       group(5), passwd(5), shadow(5), usermod(8)

DIAGNOSTICS
       The pwck command exits with the following values:

       0    Success

       1    Syntax Error

       2    One or more bad password entries

       3    Cannot open password files

       4    Cannot lock password files

       5    Cannot update password files

AUTHOR
       Julianne Frances Haugh (jockgrrl@ix.netcom.com)

																	   PWCK(1)