Multi-line bash commands in makefile

Question

Considering that every command is run in its own shell, what is the best way to run a multi-line bash command in a makefile? For example, like this:

for i in `find`
do
    all="$all $i"
done
gcc $all

Answer 1

You can use backslash for line continuation. However note that the shell receives the whole command concatenated into a single line, so you also need to terminate some of the lines with a semicolon:

foo:
    for i in `find`;     
    do                   
        all="$$all $$i"; 
    done;                
    gcc $$all

But if you just want to take the whole list returned by the find invocation and pass it to gcc, you actually don't necessarily need a multiline command:

foo:
    gcc `find`

Or, using a more shell-conventional $(command) approach (notice the $ escaping though):

foo:
    gcc $$(find)