#!perl -i.bak

$toggle = 0;

while (<>) {
  chomp if $toggle ^= 1;
  print;
}

print "\n" if $toggle;    # if the last line was chomped


##</code><code>##

#!perl -pi.bak

BEGIN { $toggle = 0; }

chomp if $toggle ^= 1;

END { print "\n" if $toggle; }