Is there a smarter alternative to “watch make”?

Question

I ran into this useful tip that if you\'re working on files a lot and you want them to build automatically you run:

watch make

And it re-runs make every couple s

Answer 1

Here is a one-liner:

while true; do make -q || make; sleep 0.5; done

Using make -q || make instead of just make will only run the build if there is something to be done and will not output any messages otherwise.

You can add this as a rule to your project's Makefile:

watch:
    while true; do $(MAKE) -q || $(MAKE); sleep 0.5; done

And then use make watch to invoke it.

This technique will prevent Make from filling a terminal with "make: Nothing to be done for TARGET" messages.

It also does not retain a bunch of open file descriptors like some file-watcher solutions, which can lead to ulimit errors.