prompt(1)

echo/Makefile

@@ -1,10 +1,13 @@
-TARGETS = echo
+TARGETS = echo prompt
 
 all: $(TARGETS)
 
-%: %.c
+echo: echo.c
 	$(CC) -o $@ $@.c
 
+prompt: echo.c
+	$(CC) -DPROMPT -o $@ echo.c
+
 clean:
 	rm -f $(TARGETS)
 

echo/echo.c

@@ -8,13 +8,18 @@ int main(int argc, char **argv){
 	if(*argv == NULL)
 		goto blank;
 	
-	while(*++argv != NULL){
-		for(i = 0; argv[0][i] != '\0'; ++i);
-		write(1, *argv, i);
+	++argv;
 
-		if(*(argv+1) != NULL)
+	while(--argc){
+		for(i = 0; argv[0][i] != '\0'; ++i);
+		write(1, *(argv++), i);
+		if(argc > 1)
 			write(1, " ", 1);
 	}
-blank:	write(1, "\n", 1);
+
+blank:
+#ifndef PROMPT
+	write(1, "\n", 1);
+#endif
 	return EX_OK;
 }