} else {
$revlist = open_pipe("git-rev-list","--parents","--remove-empty",$rev,"--",$file)
or die "Failed to exec git-rev-list: $!";
} else {
$revlist = open_pipe("git-rev-list","--parents","--remove-empty",$rev,"--",$file)
or die "Failed to exec git-rev-list: $!";