You use very confusing terminology, mixing "record", "line" and "block". Assuming that you consider "unit of work" boundary to be between a "block" 5 and a "block" 1, then why not simply use seek to seek to a position roughly ($file_size / $number_of_files) * $this_file and read forward until you've encountered one "block" 5? After that, the current set of "unit of work" starts.

I am using the below code, but its not working exactly how I would like it

#!/usr/bin/env perl
use strict;
use warnings;

my $num_files_to_write = 4;
use Data::Dumper;

my @filehandles; 
for my $id ( 1..$num_files_to_write ) {
   open ( my $fh, '>', "file_$id.txt" ) or die $!;
   push @filehandles, $fh; 
}

local $/ = '5';
while ( <> ) {
    select $filehandles[$. % $num_files_to_write];
    print; 
}

foreach my $fh ( @filehandles ) { 
   close ( $fh ); 
}
[download]

So, how does your program fail for you?

Are you saying that you want all the records starting with '1' in one file. All those starting with '2' in a second file. And all those starting with '3' in a third. And so on?

If not, you'll need to clarify your explanation because it is very confused.

Eg. What does "I need to split this large file into smaller 4 files by doing a round robin of each block(block 1 to 5)" mean?

Did you typo? Should that be "5 smaller files"?

I am sorry for the confusion. Lets say the actual file has 5 blocks as shown below(each end of block is distinguished by a record having its first character as '5'). Now, I will be dividing this actual file into 4 smaller files

Step 1: Go through the file, find the first record having the first character as '5' and copy until then to first file.

Step 2:Copy the next block until you get first character as '5' into second file and so on until the entire file is divided into 4 smaller files in round robin fashion

Actual File:

1this is block 1
2this is block 1
3this is block 1
4this is block 1
2this is block 1
3this is block 1
5this is block 1
1this is block 2
2this is block 2
3this is block 2
2this is block 2
3this is block 2
5this is block 2
1this is block 3
2this is block 3
5this is block 3
1this is block 4
2this is block 4
5this is block 4
1this is block 5
3this is block 5
5this is block 5
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File1:

1this is block 1
2this is block 1
3this is block 1
4this is block 1
2this is block 1
3this is block 1
5this is block 1
1this is block 5
3this is block 5
5this is block 5
[download]

File 2:

1this is block 2
2this is block 2
3this is block 2
2this is block 2
3this is block 2
5this is block 2
[download]

File 3:

1this is block 3
2this is block 3
5this is block 3
[download]

File 4:

1this is block 4
2this is block 4
5this is block 4
[download]

Much better explanation, thank you. Try this:

#! perl -sw
use strict;

my $file = $ARGV[0];

open I, '<', $file or die $!;

my @outs;
open $outs[ $_ ], '>', "$file.$_" or die $! for 1 .. 4;

my $out = 1;

while( <I> ) {
    print { $outs[ $out ] } $_;
    if( /^5/ ) {
         ++$out;
         $out = 1 if $out > 4;
    }
}
[download]

Call it as scriptname filename. The 4 output files will be named filename.1 filename.2 filename.3 filename.4

---

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority". I knew I was on the right track :)

In the absence of evidence, opinion is indistinguishable from prejudice.

use strict;
use warnings;

my @array = qw(
  1nkndnfd
  2nsnskdnsdn
  3ddjsjd
  4fksjsdj
  5kdsjdskjdskj
  1ksdjdjsk
  hg
  2dsjskj
  3djkdjsljs
  4fdkkjdskjsk
  5sadjjdjdodjs
  6sadjjdjdodjs
);

foreach (@array) {
    my ( $num, $data ) = /(\d)(.*)/;
    next if ( !length $num || !length $data || $num !~ /[1-5]/ );
    open my $file, '+>>', "round_robin_$num" . ".txt";
    print $file "$num - $data\n";
}
[download]

Thank you so much for taking time to look into my question

Hey no problem man, I do try to help when I can. I atleast give ideas if anything else haha :)

I think he considers each 1,2,3,4,5 as a unit and wants 4 files with round-robin units in each.

#!/usr/bin/perl
use POSIX;

my @outfile = ('file1.txt', 'file2.txt', 'file3.txt' , 'file4.txt');
my $infile = 'infile.txt';
my $lineno = 0;

open (my $ifh, '<', $infile);
while (<$ifh>) {
        my $out = $outfile[floor($lineno / 5)];
        open (my $fh, '>>', $outfile[floor($lineno / 5)%4]) or die "Un
+able to open outfile";
        print $fh $_;
        close $fh;
        $lineno++;
}
close ($ifh);
[download]

Why open & close the output files for every write?

Do you know about the variable $.?

---

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority". I knew I was on the right track :)

In the absence of evidence, opinion is indistinguishable from prejudice.

I'm in the habit of forcing a flush.

Would the flush happen regardless? If so, I've picked up something new.

--
“For the Present is the point at which time touches eternity.” - CS Lewis