Variation on myocom's technique. Could be a little more elegant with IO::File: 
use strict;
use warnings;

my ($input_file) = @ARGV;

# Auto-generate output names based on input name
my @output_file = map { "$input_file.$_" } 1..2; 

# Open up all the required filehandles
open($input_fh, "<", $input_file)
     || die "Could not open $input_file\n";

my @out_fh;

open ($out_fh[0], ">", $output_file[0])
     || die "Could not write to $output_file[0]\n";
open ($out_fh[1], ">", $output_file[1])
     || die "Could not write to $output_file[1]\n";

# Start by writing to the first filehandle
my $fh = $out_fh[0];

while (<$input_fh>)
{
      $fh = $out_fh[1] if (/^DETS01/);

      print $fh;
}

# Now close out everything
foreach my $out_fh (@out_fh)
{
      close($out_fh);
}

close($input_fh);

[download]
This rotates filehandles if the string "DETS01" occurs. The first bit is in the first file, the second in the second. So the file "input.txt" makes "input.txt.1" and "input.txt.2".

In reply to Re: How to scan a file, find a character string and print from that string to EOF by tadman
in thread How to scan a file, find a character string and print from that string to EOF by 0p3nfac3

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