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

my $input=<<END;
a,b,c,d
e,f,g,h
i,j,k,l
END

# a ref to a Perl variable can be opened for reading!
#
open IN, '<', \$input or die "cannot open var for reading";

while (<IN>)
{
   chomp;
   print;
}
#a,b,c,de,f,g,hi,j,k,l

__END__
To convert files from Windows that I transfer to Unix:
This seemingly nonsensical program converts the line endings...
when reading a Windows file on Unix...

while(<>)
{
   chomp;          # gets rid of <CR><LF> or just<LF> or just <CR>
   print "$_\n";   # new line ending is just <LF>
}