CheckAccounts is a perl script that reads meant to be run by root.
It goes through your password file, and for every account there 
checks for several error conditions.

	- The home directory exists.
	- The account does not share a home directory with anyone else.
	- The account owner also owns the files in their home direcory.
	- The shell is on an approved list.
	- There has been file activity recently.
	- The disk space used by the account is reasonable.
	- The numeric user ID is not root's.
	- If there is a shadow file, the account is also listed there.
	- All mail spool files have an associated user.
	- All entries in /etc/shadow also appear in /etc/passwd.

The parameters (how recent, how much space, etc.) of all tests
can be changed to suit the system administrator.

The intent of this program is that it is run by the administrator
periodically, and any problems discovered by the program evaluated
for potential security risks.  It is also quite useful in policing
disk usage, and deleting unused accounts.