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Re^3: removing directories with wildcard glob in OS-portable way

by BrowserUk (Pope)
on Dec 30, 2012 at 01:15 UTC ( #1010868=note: print w/replies, xml ) Need Help??


in reply to Re^2: removing directories with wildcard glob in OS-portable way
in thread removing directories with wildcard glob in OS-portable way

Trust me, the OS detection is happening, just not in your code. But that's not the problem.

It's all teh other stuff that is happening under the covers that you also don't know about.

This:

perl -E"system q[for /d %d in (scale-*) do @rd /q /s %d]"

Does the same job as this:

perl -MFile::Path -MFile::Spec -wE"File::Path::remove_tree(glob(File:: +Spec->catdir('.','scale-').'*'));"

But uses only 7% of the user cpu and 3% of the system cpu.

Does it matter? Depends alot on how big the trees are and how often you run the command I guess, but why use cycles you don't have to.


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Re^4: removing directories with wildcard glob in OS-portable way
by Anonymous Monk on Dec 30, 2012 at 03:53 UTC
    Pretty shallow trees (1 level, a few subdirs, a few thousand files total) and the operation only happens once per run (a run may persist for hours to weeks or possibly months), so this does not need to be optimized at all. I was more concerned about heading off any "why doesn't your code work on my non-*nix OS?" Will trade processor cycles for programming cycles here, I think, and avoid having to know about all those DOS /flags, and similarly for any other OS somebody tries to use.

    But that sort of thing--dropping to the system level for intensive file management--is good to know if I need increased performance for similar tasks in the future.

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davido needs to close laptop to board flight home from yapc.
[davido]: I'll look into it in a few hours probably.
[davido]: when i do get to that point I think I'll do it in a vm snapshot just in case. :)
[oiskuu]: tye, you were right: loginuid/sessionid are part of task struct if compiled with AUDITSYSCALL. I have some doubts if you should actually depend on that feature.
[Corion]: oiskuu: Depends on what you want to do with that information
[tye]: I'm not depending on that feature. But I could in this environment. I'm using getlogin(). shrug
[Corion]: For benign logging (which user started this DB instance), it's OK
[tye]: We use auditd for security monitoring. So we can rely on auditing being enabled. I'm not sure who would want to not be able to audit. Maybe some VM inside another system with audit?
[SuicideJunkie]: spies would want a system to not be able to audit.

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