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rev138
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Joined: 19 Jun 2003
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Location: Vermont, USA
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 Posted: Sun Aug 03, 2008 3:23 am Post subject: Grabbing inotifywait output in perl? |
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Invoking inotifywait with the -m flag makes it run indefinitely and print to stdout whenever an event is triggered.
I'd like to be able to invoke this from a perl script and have the script do something every time inotifywait writes to stdout, but I can't figure out how to accomplish this.
Any help is appreciated.
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widremann
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Joined: 14 Mar 2005
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| Posted: Sun Aug 03, 2008 4:07 am Post subject: |
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| You'll want to use the IPC::Open2 module (perldoc IPC::Open2) to open a filehandle to your inotifywait process. You can then read from it in a loop in your script. |
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rev138
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| Posted: Sun Aug 03, 2008 4:37 am Post subject: |
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Thanks, but I'm afraid I don't have a ton of experience with file handles in perl, and that doc talks just slightly over my head.
Could I trouble you for a short code example?
Thanks again.
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zeek
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Hu
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Joined: 06 Mar 2007
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| Posted: Sun Aug 03, 2008 4:47 pm Post subject: |
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Using an inotify module is a better solution in this case. For the more general question, consider this trivial script that runs /usr/bin/tac to print your /etc/make.conf in reverse, and sleeps as it goes: | Code: | open (CHILD, "/usr/bin/tac /etc/make.conf |") or die "Unable to open child for reading: $!";
while (<CHILD>) {
sleep 1;
print;
}
close(CHILD);
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The key point is the presence of the pipe at the end of the open statement, which directs Perl to spawn a child process, with the child's stdout set to the write end of a pipe and the read end of the pipe stored in CHILD. If you need to both read and write the child, then a more complex construct is required. |
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rev138
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Location: Vermont, USA
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| Posted: Sun Aug 03, 2008 9:00 pm Post subject: |
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Thanks all! 
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