testing if another instance of a script is already running

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    Aaron> Would it suffice to call 'os.open' with flags= _O_CREAT| _O_EXCL
    Aaron> ?  Would that be platform-independent?

I suspect it would be platform-independent but not NFS-safe.  (The other
solutions in lockfile might have NFS problems as well.  In any case,
lockfile provides a bit more functionality as well, including timeouts and
the ability to break locks.

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