/bin/sh: 1: Syntax error: word unexpected (expecting ")")

Question

I have this Makefile:

TMP_DIR := tmp
RUN_OR_NOT := $(shell date '+%y%m%d%H%M')

all: version

version:
    ifeq ($(shell test -d ${TMP_DIR} && echo -n "yes";),yes)
        $(shell echo ${TMP_DIR} already exists ...)
    else
        $(shell mkdir -p ${TMP_DIR})
    endif

I want to first check, if the directory tmp exists or not, and create it only, if it does not exist. This works, but with a strange error:

 ifeq (yes,yes)
 /bin/sh: 1: Syntax error: word unexpected (expecting ")")
 Makefile:7: die Regel für Ziel „version“ scheiterte
 make: *** [version] Fehler 2

Why is there this strange /bin/sh: 1: Syntax error: word unexpected (expecting ")") error? And how to solve this?

Answer 1

In a makefile, the recipe is a shell script. You are trying to put make constructs like ifeq into your recipe. Make will pass those to the shell and the shell throws this error because it doesn't understand makefile syntax.

You should write your recipe using shell scripting, not makefile syntax:

version:
        if test -d ${TMP_DIR}; then \
            echo ${TMP_DIR} already exists ...; \
        else \
            mkdir -p ${TMP_DIR}; \
        fi

Although why you care if the directory exists already I don't know; I would personally just use:

version:
        mkdir -p ${TMP_DIR}