Not sure if the sorting is the same. However, your code is broken and shouldn't run.

                                  v-- what's that @?
my @files = grep(/ap|ck_hm1_111/, @readdir(DIR))
[download]

Also, your regular expression needs to have the 'ap' and 'ck' grouped properly, or else you'll match a file called 'apples.txt'. If you want the files to be sorted alphabetically (let's assume lower case), you can stick in a sort block.

my @files = grep /(?:ap|ck)_hm1_111/, sort { lc $a cmp lc $b } readdir
+(DIR);
[download]

Cheers,
Ovid

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