Re^2: What's the best way to find an unused TCP port on the local system

Hmm... if I just want to know which next port (starting from e.g. 1025) is free, but without binding to it (e.g. to pass the port number to an external program) - how can that be done? I'm doing an (unportable) system "lsof -i :$port" in ssh chain to check whether it's busy. Is there a better (portable) way?

cheers,

--shmem

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

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Re^3: What's the best way to find an unused TCP port on the local system by ikegami (Patriarch) on Oct 22, 2006 at 21:13 UTC
No, it's not possible. Such a feature would unavoidably introduce a race condition. Your child process needs to either communicate the port back to you, or must inherit the opened socket from you.	[reply]