To pass non-scalars into subroutines you can use references. For example, to pass an array you can do the following.

my @array1 = ( 1, 2, 3, 4 );
my @array2 = ( 5, 6, 7, 9 );

printArrays( \@array1, \@array2 );

sub printArrays {
   my ( $first, $second ) = @_;
   print "@$first @$second\n";
}
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You can use references to pass hashes as well, you can even pass subroutines if you feel like it.

Update: To apply this to your situation...

sub printEachExpt {
   my ( $expNames, $outputPath ) = @_;
   my $total = @$expNames;
 
   print "The output path is $outputPath.\n"; 
   print "The experiment files are:\n";
   for ( 0 .. $#$expNames ) {
      print "$outputPath/$expNames->[$n]\n";
   }
   return( $expNames, $outputPath);  
}
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That should be what you want to do... untested...

Update: oh and you don't need that line with $total in there...