diff --git a/edit.c b/edit.c
index 5092c03..71b039c 100644
--- a/edit.c
+++ b/edit.c
@@ -5,7 +5,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/edit.c,v 1.106 2007/07/22 13:34:48 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/edit.c,v 1.107 2007/07/22 13:38:25 tg Exp $");
 
 /* tty driver characters we are interested in */
 typedef struct {
@@ -1697,7 +1697,7 @@ x_delete(int nc, int push)
 
 	xep -= nb;
 	cp = xcp;
-	memmove(xcp, xcp + nb, xep - xcp + 1);	/* Copies the null */
+	memmove(xcp, xcp + nb, xep - xcp + 1);	/* Copies the NUL */
 	x_adj_ok = 0;			/* don't redraw */
 	xlp_valid = false;
 	x_zots(xcp);
@@ -3476,9 +3476,9 @@ static int	modified;		/* buffer has been "modified" */
 static int	state;
 
 /* Information for keeping track of macros that are being expanded.
- * The format of buf is the alias contents followed by a null byte followed
+ * The format of buf is the alias contents followed by a NUL byte followed
  * by the name (letter) of the alias.  The end of the buffer is marked by
- * a double null.  The name of the alias is stored so recursive macros can
+ * a double NUL.  The name of the alias is stored so recursive macros can
  * be detected.
  */
 struct macro_state {
diff --git a/exec.c b/exec.c
index 1466990..c5120e8 100644
--- a/exec.c
+++ b/exec.c
@@ -2,7 +2,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/exec.c,v 1.34 2007/07/22 13:34:49 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/exec.c,v 1.35 2007/07/22 13:38:26 tg Exp $");
 
 static int comexec(struct op *, struct tbl *volatile, const char **,
     int volatile);
@@ -406,9 +406,9 @@ comexec(struct op *t, struct tbl *volatile tp, const char **ap,
 	 * before we can do a path search (in case the assignments change
 	 * PATH).
 	 * Odd cases:
-	 *   FOO=bar exec > /dev/null		FOO is kept but not exported
+	 *   FOO=bar exec >/dev/null		FOO is kept but not exported
 	 *   FOO=bar exec foobar		FOO is exported
-	 *   FOO=bar command exec > /dev/null	FOO is neither kept nor exported
+	 *   FOO=bar command exec >/dev/null	FOO is neither kept nor exported
 	 *   FOO=bar command			FOO is neither kept nor exported
 	 *   PATH=... foobar			use new PATH in foobar search
 	 */
diff --git a/misc.c b/misc.c
index 15abe55..e96db67 100644
--- a/misc.c
+++ b/misc.c
@@ -6,7 +6,7 @@
 #include <grp.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/misc.c,v 1.61 2007/07/22 13:34:51 tg Exp $\t"
+__RCSID("$MirOS: src/bin/mksh/misc.c,v 1.62 2007/07/22 13:38:26 tg Exp $\t"
 	MKSH_SH_H_ID);
 
 #undef USE_CHVT
@@ -65,7 +65,7 @@ initctypes(void)
 }
 
 /* Allocate a string of size n+1 and copy upto n characters from the possibly
- * null terminated string s into it.  Always returns a null terminated string
+ * NUL terminated string s into it.  Always returns a NUL terminated string
  * (unless n < 0).
  */
 char *
diff --git a/sh.h b/sh.h
index 3e80711..08f981b 100644
--- a/sh.h
+++ b/sh.h
@@ -8,7 +8,7 @@
 /*	$OpenBSD: c_test.h,v 1.4 2004/12/20 11:34:26 otto Exp $	*/
 /*	$OpenBSD: tty.h,v 1.5 2004/12/20 11:34:26 otto Exp $	*/
 
-#define MKSH_SH_H_ID "$MirOS: src/bin/mksh/sh.h,v 1.158 2007/07/22 13:34:51 tg Exp $"
+#define MKSH_SH_H_ID "$MirOS: src/bin/mksh/sh.h,v 1.159 2007/07/22 13:38:26 tg Exp $"
 #define MKSH_VERSION "R30 2007/07/17"
 
 #if HAVE_SYS_PARAM_H
@@ -429,9 +429,10 @@ enum sh_flag {
 
 #define Flag(f)	(shell_flags[(int) (f)])
 
-EXTERN char shell_flags [FNFLAGS];
+EXTERN char shell_flags[FNFLAGS];
 
-EXTERN char	null [] I__("");	/* null value for variable */
+/* null value for variable; comparision pointer for unset */
+EXTERN char	null[] I__("");
 
 enum temp_type {
 	TT_HEREDOC_EXP,	/* expanded heredoc */