One of the problems I've had in the past, is a need to walk a filesystem and 'batch up' files. There's a variety of reasons why - things like archiving, virus scanning, etc. Now, you _could_ do it the heavyweight way - collect a full tree directory structure, batch up that way. This didn't suit my needs - I've a billion ish files to inspect, and they change rather frequently.

So as a workaround - make use of File::Find and it's ability to prune

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

use File::Find;

my $start_from = "/path/to/search/some_dir/beneath"; 
my $count = 10_000; #how many files to grab in this 'batch'; 
my @file_list; 

sub finder {
    if ( defined $start_from and not $found ) {  
        #partial match, walk directory. 
        if ( $start_from =~ m/\QFile::Find::name/ ) {
             $File::Find::prune = 0; 
             if ( $File::Find::name =~ m/\Q$start_from/ ) {
                 $found = 1; 
             }
        }
        else {
            $File::Find::prune = 1; #don't traverse into this dir
        }
    }
    if ( @file_list > $limit ) { 
        $found = 0;
        $File::Find::prune = 1;
        return; 
    }
    return unless -f $File::Find::name;
    push ( @file_list, $File::Find::name ); 
    #backtracks a bit to the start of the current directory
    $start_from = $File::Find::dir;
}

find ( \&finder, '/path/to/search' ); 
print "Next start point: $start_from\n";

[download]

Note - as it stands, this has a limiting factor in that it'll misbehaving if the directory structure changes (e.g. $start_from no longer exists. The workaround is chopping path elements off the end until you get to a dir that _does_ exist.

Probably something like:

while ( not -d $start_from and $start_from =~ m,/, ) {
    $start_from =~ s,/[^/]+$,,;
}

[download]

(There's probably a better solution using File::Spec or similar)

In reply to Restarting File::Find by Preceptor

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.