diff --git a/build.sh b/build.sh
index ec6a7f2..28b1a18 100644
--- a/build.sh
+++ b/build.sh
@@ -46,6 +46,90 @@ success() {
 	printf "${GREEN}==> SUCCESS:${ALL_OFF}${BOLD} ${mesg}${ALL_OFF}\n" "$@"
 }
 
+# -----------------------------------------------------------------------------
+# -----------------------------------------------------------------------------
+
+# -----------------------------------------------------------------------------
+#  build
+# -----------------------------------------------------------------------------
+
+
+# -----------------------------------------------------------------------------
+#  tools
+# -----------------------------------------------------------------------------
+
+build_tools() {
+	msg "Builing tools"
+	plain "tools dir: %s" "${TOOLS_DIR}"
+
+	make tools
+}
+
+# -----------------------------------------------------------------------------
+#  doctor - check os dependancies
+# -----------------------------------------------------------------------------
+check_tool() {
+	local tool=$1; shift
+
+	printf "checking for %s " "${tool}"
+
+	tool_path="$(which "${tool}" 2> /dev/null)"
+	if [ "x${tool_path}" = "x" ]; then
+		printf "${BOLD}${RED}NO${ALL_OFF}\n"
+		false;
+	else
+		printf "${GREEN}${tool_path}${ALL_OFF}\n"
+		true;
+	fi
+}
+
+doctor() {
+	local err=0
+
+	check_tool fasm || ((err++))
+	check_tool gcc || ((err++))
+	check_tool bmake || ((err++))
+	check_tool sha256sum || ((err++))
+	check_tool python3 || ((err++))
+
+	if [ $err -gt 0 ]; then error "Some tools are missing"; fi
+}
+
+# -----------------------------------------------------------------------------
+#  usage & version
+# -----------------------------------------------------------------------------
+
+usage() {
+	local status=$1
+
+	if [ ${status} -eq 0 ]; then
+		cat <<EOF
+Usage: $prgname [-hV] [COMMANDS]
+Flags:
+	-h	display this menu.
+	-V	display version information.
+Options:
+Commands:
+	doctor
+	tools
+	build
+EOF
+	else
+		printf "Try '%s -h' for more information.\n" "${prgname}" >&2
+	fi
+
+	exit ${status}
+}
+
+version() {
+	VERSION_MAJOR="$(grep VERSION_MAJOR  kernel/const.inc  | cut -d' ' -f 3)"
+	VERSION_MINOR="$(grep VERSION_MINOR  kernel/const.inc  | cut -d' ' -f 3)"
+
+	printf "%s (StupidOS) %d.%d\n" "${prgname}" ${VERSION_MAJOR} ${VERSION_MINOR}
+
+	exit 0
+}
+
 # -----------------------------------------------------------------------------
 #  entry 
 # -----------------------------------------------------------------------------
@@ -81,8 +165,34 @@ BUILD_DIR="${topdir}/.build"
 TOOLS_DIR="${topdir}/.tools"
 TOOLS_PREFIX="stpd-"
 
-if [ $# -eq 0 ]; then
-	printf "Try '%s -h' for more information.\n" "${prgname}" >&2
-	exit 1
+export PATH="$PATH:$TOOLS_DIR"
+
+if [ ! -f Makefile ] || [ ! -f LICENSE ]; then
+	error "Run this script at StupidOS root"
 fi
 
+if [ $# -eq 0 ]; then
+	usage 1
+fi
+
+while [ $# -gt 0 ]; do
+	op=$1; shift
+	
+	case "${op}" in
+		help | --help | -h)
+			usage 0
+			;;
+		--version | -V)
+			version
+			;;
+		doctor)
+			doctor
+			;;
+		tools)
+			build_tools
+			;;
+		*)
+			usage 1
+			;;
+	esac
+done
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..add8f2b
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,2 @@
+pytest==8.0.1
+qemu.qmp==0.0.3