Question

I would like to find a file pattern on a directory pattern in Perl that will return many thousands of entries, like this:

find ~/mydir/*/??/???/???? -name "\*.$refinfilebase.search" -print

I’ve been told there are different ways to handle it? I.e.:

File::Find
glob()
opendir, readdir, grep
Diamond operator, e.g.: my @files = <$refinfilebase.search>

Which one would be most adequate to be able to run the script on older versions of Perl or minimal installations of Perl?

Answer 1

Also you have DirHandle

DirHandle:

use DirHandle;
$d = new DirHandle ".";
if (defined $d) {
    while (defined($_ = $d->read)) { something($_); }
    $d->rewind;
    while (defined($_ = $d->read)) { something_else($_); }
    undef $d;
}

For use cases of readdir and glob see
What reasons are there to prefer glob over readdir (or vice-versa) in Perl?

I prefer to use glob for quickly grab a list of files in a dir (no subdirs) and process them like

map{process_bam($_)} glob(bam_files/*.bam)

This is more convenient because it does not take the . and .. even is you ask for (*) and also returns the full path if you use a dir in the glob pattern.

Also you can use glob quickly as a oneliner piped to xargs or in a bash for loop when you need to preprocess the filenames of the list:

perl -lE 'print join("\n", map {s/srf\/(.+).srf/$1/;$_} glob("srf/198*.srf"))' | xargs -n 1.....

Readdir has adventages in other scenarios so you need to use the one that fits better for your actions.