If you want to provide arguments to a program that needs the interact with the user, why not use parameters?

#!/usr/bin/perl

die("usage: sillytest file [file [file [...]]]\n")
   if not @ARGV;

my @msg = <>;
chomp(@msg);
print(join("\n", @msg));
print "What do you want to do with this message?";
my $response = <STDIN>;
print $response;
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To pass the output of ls, you'd do
sillytest `ls`
or just
sillytest *

By the way, you might be interested in
my $msg = do { local $/; <> }; print($msg);