Guys, I have read some code that I don't quite understand, especially what the expression below on opening files. 
open (SKEL, "cat " . join (" ", @ARGV) . " |") || die "Could not open 
+$ARGV[0].\n$usage";

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I have trouble understanding what the it does, especially: "cat " . join (" ", @ARGV) . " |" Could you give me some hints? Thanks!

In reply to First post, file handle question by happyperl

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