Processing data with inotify-tools as a daemon

Question

I have a bash script that processes some data using inotify-tools to know when certain events took place on the filesystem. It works fine if run in the bash console, but when I try to run it as a daemon it fails. I think the reason is the fact that all the output from the inotifywait command call goes to a file, thus, the part after | while doesn't get called anymore. How can I fix that? Here is my script.

#!/bin/bash

inotifywait -d -r \
-o /dev/null \
-e close_write \
--exclude "^[\.+]|cgi-bin|recycle_bin" \
--format "%w:%&e:%f" \
$1|
while IFS=':' read directory event file
do

    #doing my thing

done

So, -d tells inotifywait to run as daemon, -r to do it recursively and -o is the file in which to save the output. In my case the file is /dev/null because I don't really need the output except for processing the part after the command (| while...)

Answer 1

You don't want to run inotify-wait as a daemon in this case, because you want to continue process output from the command. You want to replace the -d command line option with -m, which tells inotifywait to keep monitoring the files and continue printing to stdout:

   -m, --monitor
          Instead  of exiting after receiving a single event, execute
          indefinitely.  The default behaviour is to exit  after  the
          first event occurs.

If you want things running in the background, you'll need to background the entire script.

Answer 2

Here's a solution using nohup: (Note in my testing, if I specified the -o the while loop didn't seem to be evaluated)

nohup inotifywait -m -r \
  -e close_write \
  --exclude "^[\.+]|cgi-bin|recycle_bin" \
  --format "%w:%&e:%f" \
  $1 |
while IFS=':' read directory event file
do
  #doing my thing
done >> /some/path/to/log 2>&1 &