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 }

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

By: putnamhill

2010-10-22 23:25:12

sh sleep stat stat

5 Alternatives + Submit Alt

make, or run a script, everytime a file in a directory is modified

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..
This is sample output - yours may be different.
15

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

fain182 · 2010-06-04 17:07:03 13
Run a command when a file is changed
This is sample output - yours may be different.
12

while inotifywait -e modify /tmp/myfile; do firefox; done

anhpht · 2011-10-23 02:34:04 7
Trigger a command each time a file is created in a directory (inotify)

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
This is sample output - yours may be different.
6

inotifywait -mrq -e CREATE --format %w%f /path/to/dir | while read FILE; do chmod g=u "$FILE"; done

dooblem · 2010-10-21 23:36:02 5
make, or run a script, everytime a file in a directory is modified
This is sample output - yours may be different.
5

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

prayer · 2010-06-08 23:34:00 7
Run a command if file/directory changes

Example: runonchange /etc/nginx nginx -t Ignores vim temp files. Depends on 'inotify-tools' for monitoring of file changes. Alternative to tools like 'entr', 'watchr'.
This is sample output - yours may be different.
1

runonchange () { local cmd=( "$@" ) ; while inotifywait --exclude '.*\.swp' -qqre close_write,move,create,delete $1 ; do "${cmd[@]:1}" ; done ; }

funollet · 2015-04-08 17:42:03 10

What Others Think

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

hackerb9 · 728 weeks and 6 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..

xeor · 728 weeks and 6 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.

putnamhill · 728 weeks and 6 days ago

rahimhh21 · 110 weeks and 3 days ago

Perfecthomepugs · 101 weeks and 3 days ago

pugpuppies95 · 63 weeks and 5 days ago

yeneba6574 · 18 weeks and 3 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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