2 files changed, 3 insertions, 3 deletions
diff --git a/user/grep.c b/user/grep.c
index 19882b9..2315a0c 100644
--- a/user/grep.c
+++ b/user/grep.c
@@ -62,7 +62,8 @@ main(int argc, char *argv[])
 }
 
 // Regexp matcher from Kernighan & Pike,
-// The Practice of Programming, Chapter 9.
+// The Practice of Programming, Chapter 9, or
+// https://www.cs.princeton.edu/courses/archive/spr09/cos333/beautiful.html
 
 int matchhere(char*, char*);
 int matchstar(int, char*, char*);
diff --git a/user/user.h b/user/user.h
index b71ecda..4d398d5 100644
--- a/user/user.h
+++ b/user/user.h
@@ -1,5 +1,4 @@
 struct stat;
-struct rtcdate;
 
 // system calls
 int fork(void);
@@ -10,7 +9,7 @@ int write(int, const void*, int);
 int read(int, void*, int);
 int close(int);
 int kill(int);
-int exec(char*, char**);
+int exec(const char*, char**);
 int open(const char*, int);
 int mknod(const char*, short, short);
 int unlink(const char*);