#!/usr/bin/perl
$_ = <STDIN>; 
$arch = $_;
print $arch . "\n";
$header = substr($arch, 0, 257);  # header len is 257 total
print $header. "\n";
$header =~ s/ZZ/../g;
$before_cs = substr($header, 0, 148); # before the chksum is first 147 bytes
$after_cs = substr($header, 148+7, 100); # chksum is bytes 148 through 156 (8 bytes)
$meat = substr($arch, 148+8+100);
$sp_replace = " "x7;
$blanked_header = $before_cs . $sp_replace . $after_cs;
print $blanked_header . "\n";
my $chk;
for $offset (0..length($header)) {
  $chr = substr($header, $offset, 1);
  $chk = ord($chr) + $chk;
}
$chk = "0" + $chk;
print "checksum :$chk\n";
open ($tarfh, ">", "x.tar");
print $tarfh $before_cs . "0" . $chk . $after_cs . $meat;
close ($tarfh);