Take a look at Tie::File. That module allows for functionality such that you can treat the lines in a file the same as you would an array. No, it does not load the entire file into memory. 

#!/usr/bin/perl -w 
#####################################################

use strict;
use Tie::File;

tie my @ry,"Tie::File","myfile.txt";

my @data=(
    [ 'apple',12.2,'red' ],
    [ 'bannana', 33.3,'yellow'],
    [ 'pineapple', 17.2,'green']
    );

foreach my $dat(@data){
    push @ry,join(",",@{$dat});
}

untie @ry;

tie @ry,"Tie::File","myfile.txt";

my $t= $ry[1];
$ry[1]=$ry[0];
$ry[0]=$t;

untie @ry;

[download]
The code above gives you a file that has this for contents: 
bannana,33.3,yellow
apple,12.2,red
pineapple,17.2,green

[download]
Peter L. Berghold -- Unix Professional
Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg

In reply to Re: Persistent data storage by blue_cowdawg
in thread Persistent data storage by ssinha

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