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run a command whenever a file is touched

Terminal - run a command whenever a file is touched
ontouchdo(){ while :; do a=$(stat -c%Y "$1"); [ "$b" != "$a" ] && b="$a" && sh -c "$2"; sleep 1; done }
2010-10-22 23:25:12
User: putnamhill
Functions: sh sleep stat
10
run a command whenever a file is touched

This is useful if you'd like to see the output of a script while you edit it. Each time you save the file the command is executed. I thought for sure something like this already exists - and it probably does. I'm on an older system and tend to be missing some useful things.

Examples:

ontouchdo yourscript 'clear; yourscript somefiletoparse'

Edit yourscript in a separate window and see new results each time you save.

ontouchdo crufty.html 'clear; xmllint --noout crufty.html 2>&1 | head'

Keep editing krufty.html until the xmllint window is empty.

Note: Mac/bsd users should use stat -f%m. If you don't have stat, you can use perl -e '$f=shift; @s=stat($f); print "$s[9]\n";' $1

Alternatives

There are 3 alternatives - vote for the best!

Terminal - Alternatives
while true; do inotifywait -r -e MODIFY dir/ && make; done;
2010-06-04 17:07:03
User: fain182
15

Uses inotifywait from inotify-tools ( http://wiki.github.com/rvoicilas/inotify-tools/ ), that is compatible only with linux.

Usefull when you work with files that have to be compiled.. latex, haml, c..

inotifywait -mrq -e CREATE --format %w%f /path/to/dir | while read FILE; do chmod g=u "$FILE"; done
2010-10-21 23:36:02
User: dooblem
Functions: chmod read
6

Listens for events in the directory. Each created file is displayed on stdout. Then each fileline is read by the loop and a command is run.

This can be used to force permissions in a directory, as an alternative for umask.

More details:

http://en.positon.org/post/A-solution-to-the-umask-problem%3A-inotify-to-force-permissions

while inotifywait -r -e MODIFY dir/; do make; done;

Know a better way?

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What others think

Nice! Was this inspired by the ever useful onlogdo script? http://www.sigterm.net/projects/onlogdo

Comment by hackerb9 201 weeks and 2 days ago

Nice!

Added to my personal collection of usefull oneliners. I also added 2> /dev/null after the stat command, so I can do; ontouchdo nonexistingfile 'date', to see when that file gets created..

Comment by xeor 201 weeks and 2 days ago

@hackerb9 I'm not familiar with onlogdo, but I did have the funny feeling I was reinventing the wheel. ;) I'll check it out.

@xeor Good idea! I'll try it on my copy.

Comment by putnamhill 201 weeks and 2 days ago

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