# procedure to check if the setuid bit is on sub checkSUID { return( -u $_[0] ); }
Some file test operators
-r readable
-x executable
-e exists
-d is a directory
-t is a tty
-T text file
Example
################################################################ # Check Security ################################################################ # Users who wish to use this program must # put the file ".allowmailform" in their home directory on the # machine running this script. We don't want people creating # forms that are abused to send "anonymous" mail. $homedir = (getpwnam($recipient))[7]; if (! -e "$homedir/.allowmailform") { # this user does not permit the server to send mail to him. Quit. &error("The recipient of the form has not enabled access for this form"); exit(0); }