build: text_1 text_2
	cat text_1 text_2 > build

text_1:
	echo "Hello" > text_1

text_2:
	echo "World" > text_2

.PHONY: view clean
view:
	$(shell [ -f build ] && cat build)

clean:
	rm -f build text_1 text_2

.PHONY: echo
echo:
	echo "La commande sera affichée"
	@echo "seul le résuiltat est affiché"

VAR = "Hello"
REF = $(VAR)
EXP := $(VAR)
.PHONY: assign
assign:
	@echo "initial value: $(VAR)"
	$(eval override VAR = Bonjour)
	@echo "new value: $(VAR)"
	@echo "assign by reference \`VAR_2  = value\`: $(REF)"
	@echo "assign by expansion \`VAR_2 := value\`: $(EXP)"

.PHONY: specific
specific: text_1 text_2 build
	@echo "target.....$@"
	@echo "First dep..$<"
	@echo "All deps...$^"

TEXT = hello world
NEW_TEXT = $(subst hello, bonjour, $(TEXT))
.PHONY: subst
subst:
	@echo $(NEW_TEXT)

FILES = $(patsubst text_%,my_text_%, $(wildcard text*))
.PHONY: textfiles
textfiles: build
	@echo "origin: $(wildcard text*)"
	@echo "files: $(FILES)"

.PHONY: messages
messages:
	$(info Message d'information)
	$(warning Message d'alerte)
	$(error Message d'erreur)
	$(info Ce message ne s'affichera pas!)

EXP_FILES := $(wildcard text*)
REF_FILES = $(wildcard text*)
.PHONY: macro
macro: clean
	@echo "EXP: $(EXP_FILES)"
	@echo "REF: $(REF_FILES)"

TEST = bonjour
DIST := $(shell lsb_release -i | awk -F ':\t' '{print $$2}')
ifeq ($(DIST), Arch)
MY_MESS := "By the Way"
endif
.PHONY: condition
condition:
ifndef MY_MESS
	@echo "Vous n'utilisez pas ArchLinux : $(DIST)"
else
	@echo $(MY_MESS)
endif
ifeq ($(TEST), bonjour)
	@echo "TEST n'a pas été modifiée"
else
	@echo 'TEST a été modifiée'
endif