A usage of macros and variables.
PACKAGE = gnunode
VERSION = ` date+%Y.%m.%d `
ARCHIVE + $(PACKAGE)-$(VERSION)
dist:
tar -cf $(ARCHIVE).tar .Automatic Varialbes
$@- the target filename$*- the target filename without file extension$<- first prerequisite filename$^- filename of all prerequisites sepereated by space$+- similar to$^but includes duplicates$?- names of all prerequisites
Environment Variable Check
Variables that will take on environment variables if they exist, if not then defaults to a default value.
# if not defined in ENV variables, then take on default value '.'
GSL_INC ?= .