Inserting a new value into an already created file - perl -

i have file created has data in columns 0, 1 , 2. have new variable called $percentage has 11 values associated wish add column 3 of file.

how do without appending bottom of file?

currently data looks like, formatted next existing data:

title name number  title name number  title name number  title name number                    $percentage value 1                   $percentage value 2                   $percentage value 3                   $percentage value 4 

etc

use tie::file;

#! /usr/bin/env perl use common::sense; use tie::file;  tie @f, 'tie::file', 'foo' or die $!;  $n; (@f) {   $_ .= ' $percentage value ' . $n++; }  untie @f; 

example:

$ cat foo title name number title name number title name number title name number $ perl tie-ex  $ cat foo title name number $percentage value 0 title name number $percentage value 1 title name number $percentage value 2 title name number $percentage value 3