use MIME::Entity;

my $file = "$ARGV[0]";
open (my $fh, '<', $file) or die "Could not open file: $!";
my $out = "fixed_"."$ARGV[0]";
open (my $fhout, '>', $out) or die "Could not open file: $!";
while (<$fh>) {

file handling stuff here...
}
close($fh);
close($fhout);

my $report = MIME::Entity->build(Type=>"multipart/mixed",
From=> "me\@awesome.com",
To=> "me\@awesome.com",
Subject=> "Formatted Report- "."$ARGV[0]");

$report->attach(
                Type=>'text/plain',
                Encoding=> 'base64',
                Path=> "$ENV{HOME}",
                Filename=> "fixed_"."$ARGV[0]"
);

open MAIL, "|/usr/sbin/sendmail -t";
$report->print(\*MAIL);
close MAIL;