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

my $tempname = "rotate.$$.jpg";
my $degrees = 90;
$degrees = 270 if $0 =~ /left$/;

for my $filename (@ARGV) {
  if($filename !~ /\.jpg$/) {
    print "bad filename extension $filename\n";
    next;
  };
  if(! -e $filename) {
    print "$filename doesn't exist\n";
    next;
  };

  if(-z $filename) {
    print "$filename is zero length\n";
    next;
  };
  `jpegtran -rotate $degrees -trim $filename >$tempname` ;
  if($? == 0) { 
     rename($filename,$filename."~");
     rename($tempname,$filename);
  };
}