Hi utpalmtbi,
I agree totally with the advice of usage of some kind of database as mentioned by hdb.
However, using your dataset one can get his/her dirty using perl hash and a kind of "modified" Schwartzian transform like so: 

use warnings;
use strict;

my %hash;
my $key;

while (<DATA>) {
    next if /^\s+$/;
    if (/^>/) {
        $key = $_;
    }
    else {
        $hash{$key} = $_;
    }
}

print map { $_->[0], $hash{ $_->[0] }, $/ }
  sort { $a->[1] <=> $b->[1] }
  map { [ $_, /(\d+$)/ ] } keys %hash;

__DATA__
>or3
agagatgatagat

>or10

aacctttagtag

>or1

gtatatatata

>or2

tactacatgagg

[download]
NOTE:
I can't tell how this is do using a larger datasets..

If you tell me, I'll forget.
If you show me, I'll remember.
if you involve me, I'll understand.
--- Author unknown to me

In reply to Re: sorting headers in a file by 2teez
in thread sorting headers in a file by utpalmtbi

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