How to assign the output of a command to a Makefile variable

makefile, shell

Solution

Use the Make `shell` builtin like in `MY_VAR=$(shell echo whatever)`

me@Zack:~$make
MY_VAR IS whatever
me@Zack:~$ cat Makefile 
MY_VAR := $(shell echo whatever)

all:
    @echo MY_VAR IS $(MY_VAR)

Problem

I need to execute some make rules conditionally, only if the Python installed is greater than a certain version (say 2.5). I thought I could do something like executing: ``` python -c 'import sys; print int(sys.version_info >= (2,5))' ``` and then using the output ('1' if ok, '0' otherwise) in a `ifeq` make statement. In a simple bash shell script it's just: ``` MY_VAR=`python -c 'import sys; print int(sys.version_info >= (2,5))'` ``` but that doesn't work in a Makefile. Any suggestions? I could use any other sensible workaround to achieve this.

Original source

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