Re: Re: Re: Remove Blank Lines Off the End of a File

[jmcnamara]

Very nice.

However, it strips the last \n from the file (which probably isn't desirable) and it truncates non-whitespace data if there isn't a final \n. Which means that if you run the program twice in a row it will strip non-whitespace data from the end of the file.

Also, your tell() is followed by a read() so the next seek() starts from the EOF again and not from $cur_pos. ;-)

The following changes fix these problems:

#!/usr/bin/perl -w

use strict;

my $file = shift or die;
open my $fh, "+<$file" or die "$!";

binmode $fh; # Just in case

my $size = 4096;

my ($cur_pos, $buf);
seek $fh, -$size, 2;
while (1) {
    $cur_pos = tell $fh;
    read $fh, $buf, $size;
    last if $buf =~ m/\S/s;
    seek $fh, -$size*2, 1;
}

$buf =~ m/(\s+)$/s;
$cur_pos += $-[0] || 0;

truncate $fh, ++$cur_pos if $cur_pos;

close $fh;

exit 0;

--
John.