Without actually testing your code, that seems to be OK. A couple of things to improve it though: you should always test the return value from open,

open (DATA, "$indir/$infile") or die "Unable to open $indir/$infile: $
+!";
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would be a conventional way of doing that. Notice also that read returns the number of bytes read, which you can use to check that you get back the number you expect - if data can be wrong it will be!