#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

sub shell_quote_arg {
   my ($s) = @_;
   return $s if $s =~ /[^-\/@=_0-9a-z]/i;
   $s =~ s/'/'"'"'/g;
   return qq{'$s'}
}

sub shell_quote {
    return join ' ', map { shell_quote_arg($_) } @_;
}

print shell_quote('echo', q{He's got $100});