Re^3: listing all subdirectories of directory into file

[aaron_baugher]

At first I thought File::Find might not be that good for this, because he wants to make a list within each directory of its subdirectories, which at first glance means "looking at" each directory twice: once when you're adding it to its parent directory's list, and then again when File::Find comes across it. But then I thought of this, which is very simple, but has the downside of opening the output file every time it needs to write a line:

#!/usr/bin/env perl
use Modern::Perl;
use File::Find;

sub w {
    if( -d $_ ){
        open my $out, '>>', 'list' or die $!;
        print $out "$_\n";
        close $out;
    }
}
File::Find::find(\&w, '.');

[jdrago999]

Why open and close $out every time?

#!/usr/bin/env perl
use Modern::Perl;
use File::Find;

# $out is used within w():
open my $out, '>>', 'list' or die $!;

sub w {
    if( -d $_ ){
        print $out "$_\n";
    }
}
File::Find::find(\&w, '.');

[aaron_baugher]

If you look at his spec, he wants more than one "out" file. In each directory, he wants a file named 'list' that contains a list of every subdirectory of that directory. So in a directory structure like the following, you would get 'list' files like so:

$ find . -ls|cut -b14-24,68-
drwxr-xr-x  .
drwxr-xr-x  ./a
-rw-r--r--  ./a/list
drwxr-xr-x  ./a/d
drwxr-xr-x  ./a/c
drwxr-xr-x  ./b
-rw-r--r--  ./list
$ cat list
a
b
$ cat a/list
c
d