Perldoc is your friend here.

From your $dir path, looks like you are on windows. So go to a DOS prompt, enter:

perldoc -f readdir

and you will see by happy coincidence as the example in the last paragraph an answer to your question:

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If you're planning to filetest the return values out of a "readdir", you'd better prepend the directory in question. Otherwise, because we didn't "chdir" there, it would have been testing the wrong file.

opendir(DIR, $some_dir) || die "can't opendir some_dir: $!";
@dots = grep { /^\./ && -f "$some_dir/$_" } readdir(DIR);
closedir DIR;
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Just replace the ^\. with ^xxxx and your job is done, like:

opendir(DIR, $some_dir) || die "can't opendir $some_dir: $!";
@xxxx = grep { /^xxxx/ && -f "$some_dir/$_" } readdir(DIR);
closedir DIR;

print "@xxxx";
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