[user]$ cat test.pl
#!/usr/bin/perl
print "This is a suid test\n";
[user]$ chmod +s test.pl
[user]$ ll rover.pl
-rwsr-xr-x    1 user coders        203 Mar 10 02:41 test.pl
[user]$ ./test.pl
Can't do setuid
[user]$ su root
Password:
[root]# ./test.pl
This is a suid test
[root]# exit
exit
[user]$ ./test.pl
Can't do setuid
$ uname -sr
Linux 2.4.18-27.7.xsmp
$