Hello monks,

I'm using the following code to remove new line characters from the end of a data file. 

#!/perl/bin/perl.exe -w

use strict;
use vars qw($cur_pos $buf);

my $file = $ARGV[0];

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

    my $size = 4096;

    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;

[download]
And this is what I'm using for a data file 
0x130002a; 12.23.34.45; 0x2c60021; RstoneSwRtr
0x130009d; 12.23.34.45; 0x3c6000e; LucentP550R
0x13000fa; 1.2.3.4; 0x21000c; Rtr_Cisco
0x130012e; 1.2.3.4; 0x21000c; Rtr_Cisco
0x1300183; 1.2.3.4; 0x21b001d; 6H262_18
0x13001a8; 1.2.3.4; 0x2c60021; RstoneSwRtr
0x13001f9; 1.2.3.4; 0x21000c; Rtr_Cisco

[download]

The problem is that truncate is removing everything from the underscore in Rtr_Cisco down instead of leaving Rtr_Cisco intact.

data file looks like this after truncated 

0x130002a; 12.23.34.45; 0x2c60021; RstoneSwRtr
0x130009d; 12.23.34.45; 0x3c6000e; LucentP550R
0x13000fa; 1.2.3.4; 0x21000c; Rtr_Cisco
0x130012e; 1.2.3.4; 0x21000c; Rtr_Cisco
0x1300183; 1.2.3.4; 0x21b001d; 6H262_18
0x13001a8; 1.2.3.4; 0x2c60021; RstoneSwRtr
0x13001f9; 1.2.3.4; 0x21000c; Rtr_

[download]
Does anyone have any idea whats going wrong?
Thanks

In reply to File Truncation Problem by The_Rev

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