Make Quick Reference

Inside Makefile:

TARGET: DEPENDENCY LINE OR RULES LINE

COMMAND
COMMAND
...

A command line (with TAB in front) is running in a subshell by itself.

# A comment.
name = text in name	Macro definition.
$A	Single character macro reference.
$(name) or ${name}	Macro references.
make -p	Print internally defined macros.
make target "DIR=/dir /dir2"	Use DIR defined in command even if you defined DIR in your Makefile!
DIR=/bin make target	Use DIR in Makefile if any, otherwise use DIR=/bin.
make -e	Shell variables have higher priority than file macro definitions.
FILE=a.c b.c @echo ${FILE:.c=.o} a.o b.o	Replace suffix .c by .o. The @ suppress the printing of commands executed.
$@	Current target. Use in command line only.
$?	List of pre-requisites newer than current target. Use in command line only.
$$@	Current target. Use in dependency line only.
$*	File name without suffix part. Use in commands in suffix rule only.
$%	Name of the .o when target is a library module.
$<	The pre-requisite file. Use in commands in suffix rule only.
.SUFFIXES: .o .c	Suffixes that make will consider.
.c.o: ${CC} -c $<	Suffix rule. To produce .o from a .c.
t: libm.a(sin.o)	Target t depends on sin.o in libm.a. Hence, if sin.o is newer than libm.a, implicit rule replace newer sin.o into libm.a, then create target t.
libm.a :: sin.c libm.a :: cos.c	Rebuild libm.a using different commands depends on the pre-requisites.
- rm -f *.o	Ignore errors in the command rm, hence, errors will not stop the make process.
t: a.c \ b.c	Use '\' to continue with the next line.
.SUFFIXES: .SUFFIXES: .a .b .SUFFIXES: .c	1. Clear implicit suffixes. 2. Define .a .b suffixes. 3. Add .c into the suffix list.
.c.a: true	Override default suffix rule with null command
t: echo $$HOME	Use $$ in commands for environment variable.
.IGNORE	Force make to ignore errors and keep going.
${<D}, ${<F}	Pre-requisite file directory, pre-requisite file name.
VPATH	View path.
include inc.mk	Include the file inc.mk.
.PRECIOUS: a.x b.x	Do not let make deletes files a.x and b.x.
.SILENT	Do not echo commands while executing.
.DEFAULT: echo "hello"	Define a default action.

Reference: C Programming Utility: Managing Projects with make by Andrew Oram and Steve Talbott