diff --git a/user/diagdummy/.gitignore b/user/diagdummy/.gitignore
new file mode 100644
index 0000000..a3dd283
--- /dev/null
+++ b/user/diagdummy/.gitignore
@@ -0,0 +1,2 @@
+*.o
+diagdummy
diff --git a/user/diagdummy/Makefile b/user/diagdummy/Makefile
new file mode 100644
index 0000000..c7e69f8
--- /dev/null
+++ b/user/diagdummy/Makefile
@@ -0,0 +1,24 @@
+include $(ROOT)/mk/grabsrc.mk
+include ../Makefile.inc
+
+.PHONY: all clean
+
+TARGET := diagdummy
+
+LDFLAGS += -L$(ROOT)/ulib -l:libulib.a
+
+SRCFILES := $(call GRABSRC, .)
+CFILES := $(call GET_CFILES, $(SRCFILES))
+OBJ := $(call GET_OBJ, $(SRCFILES))
+
+%.o: %.c
+	$(CC) $(CFLAGS) -c $< -o $@
+
+all: $(TARGET)
+
+$(TARGET): $(OBJ)
+	$(LD) $^ $(LDFLAGS) -o $@
+	echo $$(realpath $(TARGET)) >> $(FILES)
+
+clean:
+	rm -f $(OBJ) $(TARGET)
diff --git a/user/diagdummy/block.c b/user/diagdummy/block.c
new file mode 100644
index 0000000..6a31b32
--- /dev/null
+++ b/user/diagdummy/block.c
@@ -0,0 +1,7 @@
+#include <ulib.h>
+
+void diagdummy_block(void) {
+  uprintf("blocking...\n");
+  while(1) {
+  }
+}
diff --git a/user/diagdummy/block.h b/user/diagdummy/block.h
new file mode 100644
index 0000000..cee21ca
--- /dev/null
+++ b/user/diagdummy/block.h
@@ -0,0 +1,6 @@
+#ifndef DIAGDUMMY_BLOCK_H_
+#define DIAGDUMMY_BLOCK_H_
+
+void diagdummy_block(void);
+
+#endif // DIAGDUMMY_BLOCK_H_
diff --git a/user/diagdummy/diagdummy.c b/user/diagdummy/diagdummy.c
new file mode 100644
index 0000000..815a1f1
--- /dev/null
+++ b/user/diagdummy/diagdummy.c
@@ -0,0 +1,17 @@
+#include <ulib.h>
+#include "block.h"
+
+void main(void) {
+  if (argslen() == 0) {
+    uprintf("diagdummy: no arguments\n");
+    quit();
+  }
+
+  char *cmd = args()[0];
+
+  if (string_strcmp(cmd, "block") == 0) {
+    diagdummy_block();
+  } else {
+    uprintf("diagdummy: unknown cmd %s\n", cmd);
+  }
+}