inotify and bash

Question

I am trying to make a bash script with inotify-tools that will monitor a directory and alter all new files by removing lines containing "EE". Once altered it will move the files to another directory

    #!/bin/sh     while inotifywait -e create /home/inventory/initcsv; do       sed '/^\"EE/d' Filein > fileout #how to capture File name?       mv fileout /home/inventory/csvstorage     fi     done 

Please help?

Answer 1

By default, the text output from inotifywait -e CREATE is of form

     watched_filename CREATE event_filename 

where watched_filename represents /home/inventory/initcsv and event_filename represents the name of the new file.

So, in place of your while inotifywait -e ... line, put:

    DIR=/home/inventory/initcsv     while RES=$(inotifywait -e create $DIR); do         F=${RES#?*CREATE } 

and in your sed line use $F as the Filein name. Note, the $(...) construction is posix-compatible form of process substitution (often done using backticks) and the ${RES#pattern} result is equal to $RES with the shortest pattern-matching prefix removed. Note, the last character of the pattern is a blank. [See update 2]

Update 1 To handle file names that may contain whitespace, in the sed line use "$F" instead of $F. That is, use double quotes around the reference to value of F.

The RES=... and F=... definitions do not need to use double quotes, but it is ok to use them if you like; for example: F=${RES#?*CREATE } and F="${RES#?*CREATE }" both will work ok when handling filenames containing whitespace.

Update 2 As noted in Daan's comment, inotifywait has a --format parameter that controls the form of its output. With command

while RES=$(inotifywait -e create $DIR --format %f .)    do echo RES is $RES at `date`; done 

running in one terminal and command

touch a aa; sleep 1; touch aaa;sleep 1; touch aaaa 

running in another terminal, the following output appeared in the first terminal:

Setting up watches. Watches established. RES is a at Tue Dec 31 11:37:20 MST 2013 Setting up watches. Watches established. RES is aaa at Tue Dec 31 11:37:21 MST 2013 Setting up watches. Watches established. RES is aaaa at Tue Dec 31 11:37:22 MST 2013 Setting up watches. Watches established. 

Answer 2

The output from inotifywait is of the form:

filename eventlist [eventfilename] 

If your file names can contain spaces and commas, this gets tricky to parse. If it only contains 'sane' file names, then you can do:

srcdir=/home/inventory/initcsv tgtdir=/home/inventory/csvstorage inotifywait -m -e create "$directory" | while read filename eventlist eventfile do     sed '/^"EE/d'/' "$srcdir/$eventfile" > "$tgtdir/$eventfile" &&     rm -f "$srcdir/$eventfile done