What reasons are there to prefer glob over readdir (or vice-versa) in Perl?

Question

This question is a spin-off from this one. Some history: when I first learned Perl, I pretty much always used glob rather than opendir + read

Answer 1

glob makes it convenient to read all the subdirectories of a given fixed depth, as in glob "*/*/*". I've found this handy in several occasions.

Answer 2

First, do some reading. Chapter 9.6. of the Perl Cookbook outlines the point I want to get to nicely, just under the discussion heading.

Secondly, do a search for glob and dosglob in your Perl directory. While many different sources (ways to get the file list) can be used, the reason why I point you to dosglob is that if you happen to be on a Windows platform (and using the dosglob solution), it is actually using opendir/readdir/closedir. Other versions use built-in shell commands or precompiled OS specific executables.

If you know you are targetting a specific platform, you can use this information to your advantage. Just for reference I looked into this on Strawberry Perl Portable edition 5.12.2, so things may be slightly different on newer or original versions of Perl.

Answer 3

glob pros: Can return 'filenames' that don't exist:

my @deck = List::Util::shuffle glob "{A,K,Q,J,10,9,8,7,6,5,4,3,2}{\x{2660},\x{2665},\x{2666},\x{2663}}";
while (my @hand = splice @deck,0,13) {
    say join ",", @hand;
}
__END__
6♥,8♠,7♠,Q♠,K♣,Q♦,A♣,3♦,6♦,5♥,10♣,Q♣,2♠
2♥,2♣,K♥,A♥,8♦,6♠,8♣,10♠,10♥,5♣,3♥,Q♥,K♦
5♠,5♦,J♣,J♥,J♦,9♠,2♦,8♥,9♣,4♥,10♦,6♣,3♠
3♣,A♦,K♠,4♦,7♣,4♣,A♠,4♠,7♥,J♠,9♥,7♦,9♦

Answer 4

For small, simple things, I prefer glob. Just the other day, I used it and a twenty line perl script to retag a large portion of my music library. glob, however, has a pretty strange name. Glob? It's not intuitive at all, as far as a name goes.

My biggest hangup with readdir is that it treats a directory in a way that's somewhat odd to most people. Usually, programmers don't think of a directory as a stream, they think of it as a resource, or list, which glob provides. The name is better, the functionality is better, but the interface still leaves something to be desired.