diff --git a/intro/Makefile b/intro/Makefile
index aa6a065..ee7b895 100644
--- a/intro/Makefile
+++ b/intro/Makefile
@@ -4,7 +4,12 @@ CFLAGS += -Wall -lunp
 objs = $(basename $(srcfiles))
 
 all:
+	@mkdir -p build;
 	@for obj in $(objs); do \
 		$(CC) $$obj.c $(CFLAGS)  -o build/$$obj; \
 	done
-.PHONY: all
\ No newline at end of file
+	
+clean:
+	@rm -rf build/*
+
+.PHONY: all clean
\ No newline at end of file
diff --git a/select/Makefile b/select/Makefile
index aa6a065..ac8c041 100644
--- a/select/Makefile
+++ b/select/Makefile
@@ -4,7 +4,10 @@ CFLAGS += -Wall -lunp
 objs = $(basename $(srcfiles))
 
 all:
+	@mkdir -p build;
 	@for obj in $(objs); do \
 		$(CC) $$obj.c $(CFLAGS)  -o build/$$obj; \
 	done
-.PHONY: all
\ No newline at end of file
+clean:
+	@rm -rf build/*
+.PHONY: all clean
\ No newline at end of file
diff --git a/sockopt/Makefile b/sockopt/Makefile
index aa6a065..ac8c041 100644
--- a/sockopt/Makefile
+++ b/sockopt/Makefile
@@ -4,7 +4,10 @@ CFLAGS += -Wall -lunp
 objs = $(basename $(srcfiles))
 
 all:
+	@mkdir -p build;
 	@for obj in $(objs); do \
 		$(CC) $$obj.c $(CFLAGS)  -o build/$$obj; \
 	done
-.PHONY: all
\ No newline at end of file
+clean:
+	@rm -rf build/*
+.PHONY: all clean
\ No newline at end of file
diff --git a/tcpclisrv/Makefile b/tcpclisrv/Makefile
index aa6a065..ac8c041 100644
--- a/tcpclisrv/Makefile
+++ b/tcpclisrv/Makefile
@@ -4,7 +4,10 @@ CFLAGS += -Wall -lunp
 objs = $(basename $(srcfiles))
 
 all:
+	@mkdir -p build;
 	@for obj in $(objs); do \
 		$(CC) $$obj.c $(CFLAGS)  -o build/$$obj; \
 	done
-.PHONY: all
\ No newline at end of file
+clean:
+	@rm -rf build/*
+.PHONY: all clean
\ No newline at end of file
diff --git a/udpclisrv/Makefile b/udpclisrv/Makefile
index aa6a065..ac8c041 100644
--- a/udpclisrv/Makefile
+++ b/udpclisrv/Makefile
@@ -4,7 +4,10 @@ CFLAGS += -Wall -lunp
 objs = $(basename $(srcfiles))
 
 all:
+	@mkdir -p build;
 	@for obj in $(objs); do \
 		$(CC) $$obj.c $(CFLAGS)  -o build/$$obj; \
 	done
-.PHONY: all
\ No newline at end of file
+clean:
+	@rm -rf build/*
+.PHONY: all clean
\ No newline at end of file