Well, you haven't given us much to go on, but it sounds like you have the right idea: 
my $newdir = "$directory\/$month\/$day"
if (!(-e $newdir)) {
 mkdir $newdir, 0755 or die "couldn't mkdir $newdir because: $!\n";
}

[download]
Scott

updated per tilly's suggestion.

In reply to Re: Avoiding making a directory that already exists by scain
in thread Avoiding making a directory that already exists by Anonymous Monk

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