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I know at least three ways to monitor a folder/file for changes and execute a shell script on change.

  • First, use "Folder Actions" of Automator

  • Second, the launchd.plist approach but it seems the folder been monitored couldn't go through recursively.

  • Third, use native FSEvents API on Mac OS X. like the modified fswatch utility

My question is that which one cost system resource (CPU or memory) less ?

share|improve this question
It's probably safe to assume that the first two rely on the third -> all are rather efficient. – patrix Jan 3 '13 at 16:08
Folder actions are also limited to a single folder without subfolders. And they are only run when files are added, not when they are modified. – user495470 Jan 3 '13 at 18:31

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