Hello demo program

Makefile

@@ -120,6 +120,7 @@ mkfs/mkfs: mkfs/mkfs.c $K/fs.h $K/param.h
 UPROGS=\
 	$U/_cat\
 	$U/_echo\
+	$U/_hello\
 	$U/_forktest\
 	$U/_grep\
 	$U/_init\

user/hello.c

@@ -0,0 +1,13 @@
+#include "kernel/types.h"
+#include "kernel/stat.h"
+#include "user/user.h"
+
+int
+main(int argc, char *argv[])
+{
+  char hello[] = "Hello XV6!\n";
+
+  write(1, hello, sizeof(hello));
+
+  exit(0);
+}