python - How can I "watch" a file for modification / change?

Question

I would like to invoke my chrome or firefox browser when a file that I specify is modified. How could I "watch" that file to do something when it gets modified?

Programmatically it seems the steps are.. basically set a never ending interval every second or so and cache the initial modification date, then compare the date every second, when it changes invoke X.

Follow this tutorial on using inotify Inotify Example: Introduction to Inotify with a C Program Example — thegeek
This is not a duplicate question, as that question is about windows. — interestedparty333

Matthew Flaschen Matthew Flaschen · Accepted Answer · 2010-07-18T04:54:26

As noted, you can use pyinotify:

E.g.:

import webbrowser
import pyinotify

class ModHandler(pyinotify.ProcessEvent):
    # evt has useful properties, including pathname
    def process_IN_CLOSE_WRITE(self, evt):
            webbrowser.open(URL)

handler = ModHandler()
wm = pyinotify.WatchManager()
notifier = pyinotify.Notifier(wm, handler)
wdd = wm.add_watch(FILE, pyinotify.IN_CLOSE_WRITE)
notifier.loop()

This is more efficient than polling. The kernel tells you when it does the operation, without you having to constantly ask.

python - How can I "watch" a file for modification / change?

7 Answers