Makefile command substitution problem

Question

rebar doesn\'t automatically rebuild files when given a different configuration file. So, I\'ve tried to do it on the Makefile level:

REBAR=./rebar
REBAR_DEB         


        

Answer 1

You can also use the shell assignment operator

LAST_CONFIG != cat config.tmp

§ How make Reads a Makefile

Example

Answer 2

You're missing the part where you need to use shell in order to actually call external programs when defining a variable.

LAST_CONFIG:=$(shell cat config.tmp)