I think you have mis-understood the comment about prototypes. I suspect that you probably didn't even know that you were declaring a prototype.

The simple explanation is: when you define a sub X, do not put parens, () after the name.
That's it.
sub X(){} means something very different than just sub X{}.
I would go as far as to say that you never have to, and normally should not put any (....stuff...) after the sub's name.

-What you have done with shift is 100% correct.
-Maybe chomp() is not necessary, but it doesn't "hurt".
-A more important point for me is to indent the lines within the subroutine by either 3 or 4 spaces.

"Prototype failure" example:

#!/usr/bin/perl -w
use strict;

# This sequence works, although with a warning...
# because Perl hasn't yet seen subroutine X.

X("xyz");

sub X()  # this means that subroutine X cannot 
         # be called with any arugment at all.
         # sub X();      #is ok, 
         # sub X("abc"); #is not ok.
{
   my $input = shift;
   print "$input\n";
}

#this would fail to produce a result - program fails to compile
# X("abc");  
# because now that subroutine X() has been seen, it is understood
# that no arguments can be passed to it.

__END__
prints:
main::X() called too early to check prototype at C:\TEMP\prototypes.pl
+ line 4.
xyz
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