#!/bin/sh
# If you are not passing bash var's into the PERL HEREDOC,
# then single quote the HEREDOC tag
perl -le "$(cat <<'MYPL'
# Best to build your out vars rather than writing directly
# to the pipe until the end.
my $STDERRdata="", $STDOUTdata="";
while ($i=<STDIN>){ chomp $i;
 $STDOUTdata .= "To stdout\n";
 $STDERRdata .= "Write from within the heredoc\n";
MYPL
print $STDOUTdata; # Doing the pipe write at the end will save you
warn $STDERRdata;  # a lot of frustration.
)" <myInputFile 1>prints.txt 2>warns.txt