FAQ 5.33 How do I dup() a filehandle in Perl?

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5.33: How do I dup() a filehandle in Perl?

    If you check "open" in perlfunc, you'll see that several of the ways to
    call open() should do the trick. For example:

            open(LOG, ">>/foo/logfile");
            open(STDERR, ">&LOG");

    Or even with a literal numeric descriptor:

       $fd = $ENV;
       open(MHCONTEXT, "<&=$fd");   # like fdopen(3S)

    Note that "<&STDIN" makes a copy, but "<&=STDIN" make an alias. That
    means if you close an aliased handle, all aliases become inaccessible.
    This is not true with a copied one.

    Error checking, as always, has been left as an exercise for the reader.


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