Basic if else statement in Makefile

Question

I\'m trying to execute a simple if else statement in a Makefile:

check:
  if [ -z \"$(APP_NAME)\" ]; then \\
    echo \"Empty\" \\
  else \\
    echo \"Not e         


        

Answer 1

This is shell syntax, not makefiles. You need to familiarize yourself with the rules surrounding using backslashes to enter long commands into a single line of shell.

In your example, after the backslash newline pairs are removed, it looks like this:

if [ -z "$(APP_NAME)" ]; then echo "Empty" else echo "Not empty" fi

Maybe you can now see that the issue is. The shell interprets that as:

if [ -z "$(APP_NAME)" ]; then

followed by a single long command:

echo "Empty" else echo "Not empty" fi

which would echo the content Empty else echo not empty fi, except that since there's no trailing fi shell token it's instead a syntax error.

In shell syntax you need to add a semicolon after every individual command, so the shell knows how to split it up:

check:
        if [ -z "$(APP_NAME)" ]; then \
            echo "Empty"; \
        else \
            echo "Not empty"; \
        fi

Note the semicolons after the echo commands telling the shell that the command arguments end there.