CODEWITHSUNDEEP
gitmakefile
Stephen Rasku
Stephen Rasku

Reputation: 2682

Setting Makefile variable to result of command in rule

I am trying to assign the result of a command to a variable in GNU make. It works if I do it outside the rule:

$ cat stack.mk
GIT_BRANCH=$(shell git rev-parse --abbrev-ref HEAD)

all:
    @echo Git branch is $(GIT_BRANCH)

$ make -f stack.mk all
Git branch is dev

But not if I put it in the rule body:

$ cat stack.mk
all:
    export GIT_BRANCH=$(shell git rev-parse --abbrev-ref HEAD)
    @echo Git branch is $(GIT_BRANCH)

$ make -f stack.mk all
export GIT_BRANCH=dev
Git branch is

Is it possible to assign variables in a rule. At this point I would like to assign the results of a couple of git commands to shell/Makefile variables.

Upvotes: 8

Views: 15383

Answers (1)

merlin2011
merlin2011

Reputation: 75575

Yes, if you are trying to set a Makefile variable, you can do it using eval function. 

all:
    $(eval GIT_BRANCH=$(shell git rev-parse --abbrev-ref HEAD))
    echo Git branch is $(GIT_BRANCH)

Upvotes: 35

Related Questions