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

I do it this way in my Makefile:

watch:
    (while true; do make build.log; sleep 1; done) | grep -v 'make\[1\]'

build.log: ./src/*
    thecompiler | tee build.log

So, it will only build when my source code is newer than my build.log, and the "grep -v" stuff removes some unnecessary make output.

Answer 2

Using classic gnu make and inotifywait, without interval-based polling:

watch:
    while true; do \
        make $(WATCHMAKE); \
        inotifywait -qre close_write .; \
    done

This way make is triggered on every file write in the current directory tree. You can specify the target by running

make watch WATCHMAKE=foo

Answer 3

Twitter Bootstrap uses the watchr ruby gem for this.

https://github.com/twbs/bootstrap/blob/v2.3.2/Makefile

https://github.com/mynyml/watchr

Edit:

After two years the watchr project seems not to be maintained anymore. Please look for another solution among the answers. Personally, if the goal is only to have a better output, i would recommend the answer from wch here

Answer 4

There are several automatic build systems that do this and more - basically when you check a change into version control they will make/build - look for Continuous Integration

Simple ones are TeamCity and Hudson

Answer 5

How about

# In the makefile:
.PHONY: continuously
continuously:
    while true; do make 1>/dev/null; sleep 3; done  

?

This way you can run

make continuously

and only get output if something is wrong.