There are two functions you can use to get the contents of a directory. glob and readdir. glob is the slowest, but allows you to limit the types of files you get back. eg

my @files = glob("*_hm1_111");
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will return you all files ending with hm1_111, but you need more flexibility than this, so readdir is probably the best choice.

readdir on the other hand is very fast, and returns you the files in whatever order they are stored in the internal representation for your file system. This will not always be alpha/ascii-betical. glob always returns files sorted ascii-betically.

The last difference between the two is how . (dot) files are handled. glob("*") will not return files such as .bashrc but readdir will. glob(".*") must be called if you want the . files. (In fact glob works very much like the UNIX c-shell.)

Having said all of this, I'd suggest you use ovid's suggestion in most circumstances. However, if it is likely that your directory contents will be very large (and you are only interested in a small fraction of the files) and if performance is important then I'd suggest you compare ovid's suggestion with something like this:

my @files = grep /^(?:ap|ck)_hm1_111/, glob("DIR/*_hm1_111");
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and go with the best.

Jacinta