Re^3: Modify a txt file

[GrandFather]

The code you posted works as advertised by davido. Consider:

use strict;
use warnings;

my $data = <<DATA;
0       ASDF
        ASEE
        ASEE

13      DERG
        DREG

28      QWER
        QWER

42      WERT
        WERT
        WERT

55      QWEASD
        QWEASD
        QWEASD
        QWEASD

DATA

open my $inFile, '<', \$data;

$/ = "\n\n";

while (<$inFile>) {
    if (my ($number) = m/(\d+)/) {
        s/\b\p{Alpha}+\b/$number/g;
    } else {
        warn "Malformed record in input line $.\n$_\nContinuing.\n";
    }
    print;
}

Prints:

0       0
        0
        0

13      13
        13

28      28
        28

42      42
        42
        42

55      55
        55
        55
        55

so there is a mismatch between what you are telling us and what you are actually doing. If you really want help you need to really tell us what you are doing and show us (as per the sample code above) how things are going wrong. We can't fix what ain't broke!