diff --git a/user/sh.c b/user/sh.c
index 83dd513..36245b3 100644
--- a/user/sh.c
+++ b/user/sh.c
@@ -52,6 +52,7 @@ struct backcmd {
 int fork1(void);  // Fork but panics on failure.
 void panic(char*);
 struct cmd *parsecmd(char*);
+void runcmd(struct cmd*) __attribute__((noreturn));
 
 // Execute cmd.  Never returns.
 void