Thank-you, I will try that.

This is what I've tried to date, with help to build the if clauses with expressions, but as soon as I removed the first $ record it broke, and I'm still none the wiser as to why

#!/usr/bin/perl

use strict;
use warnings;

open my $data_fh, '<', 'data.txt' or die "could not open data.txt: $!\
+n";
open my $dollar_fh, '>', 'dollar.txt' or die "could not open dollar.tx
+t: $!\n"; 
open my $star_fh, '>', 'asterisk.txt' or die "could not open asterisk.
+txt: $!\n";
open my $percent_fh, '>', 'percent.txt' or die "could not open dollar.
+txt: $!\n";

while( <$data_fh> ){
  chomp;
  while( length ){

    if( s{ (\d+) \$ }{}msx ){
      my $len = $1;
      my $data = substr( $_, 0, $len, '' );
      print $dollar_fh "$data\n" or die "could not print to dollar.txt
+: $!\n";
    }

    if( s{ (\d+) \* }{}msx ){
      my $len = $1;
      my $data = substr( $_, 0, $len, '' );
      print $star_fh "$data\n" or die "could not print to asterisk.txt
+: $!\n";
    }

    if( s{ (\d+) \% }{}msx ){
      my $len = $1;
      my $data = substr( $_, 0, $len, '' );
      print $percent_fh "$data\n" or die "could not print to percent.t
+xt: $!\n";
    }

  }
}

close $dollar_fh or die "could not close dollar.txt: $!\n";
close $star_fh or die "could not close asterisk.txt: $!\n";
close $percent_fh or die "could not close percent.txt: $!\n";
close $data_fh or die "could not close data.txt: $!\n";
[download]

Thanks!