You have the perl -s at the top of the script but then you run the script with perl on the command line. Pick one. Either set the script to have execute permissions and then run the script or run the script from the command line with the -s option.

bruce:0:~/tmp $ cat p.pl
#!/usr/bin/perl -s
#
if ($foo eq "bar") { print "true\n" }
bruce:0:~/tmp $ ls -l p.pl
-rwxr-xr-x   1 bruce  bruce  59 Aug  5 08:36 p.pl
bruce:0:~/tmp $ ./p.pl -foo=bar
true
bruce:0:~/tmp $ perl p.pl -foo=bar
bruce:0:~/tmp $ 
bruce:0:~/tmp $ perl -s p.pl -foo=bar
true