I could have made it clearer ;-)

You can actually avoid opening all the file handles with a small sub: 

my %handles;
sub handle_for_name {
    my $f = shift;
    if ($handles{$f}){
        return $handles{$f};
    } else {
        open my $h, '<', $f or die "Can't open file '$f': $!";
       $hanldes{$f} = $h;
       return $h;
    }
}

[download]

And then whenever you need a file handle you just call that function that opens the file if it's not already opened.

You can make that sub even smaller with a neat little trick: 

use Memoize;
memoize("handle_for_name");
sub handle_for_name {
    my $f = shift;
    open my $h, '<', $f or die "Can't open file '$f': $!";
    return $h;
}

[download]

That's magic, eh?

To answer your original question: if you have a file handle in a lexical variable $h, you can use if ($fh){ print "file opened\n"}

In reply to Re^3: How can you check to see if a file handle is already open? by moritz
in thread How can you check to see if a file handle is already open? by agent_smith

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