diff --git a/bin/sh/alias.c b/bin/sh/alias.c
index c815b9289a32..0b7e31a2dbb1 100644
--- a/bin/sh/alias.c
+++ b/bin/sh/alias.c
@@ -246,7 +246,7 @@ aliascmd(int argc, char **argv)
 	while ((n = *++argv) != NULL) {
 		if ((v = strchr(n+1, '=')) == NULL) /* n+1: funny ksh stuff */
 			if ((ap = lookupalias(n, 0)) == NULL) {
-				outfmt(out2, "alias: %s not found\n", n);
+				warning("%s not found", n);
 				ret = 1;
 			} else
 				printalias(ap);
diff --git a/bin/sh/bltin/bltin.h b/bin/sh/bltin/bltin.h
index 6618108d350f..f6e788365aad 100644
--- a/bin/sh/bltin/bltin.h
+++ b/bin/sh/bltin/bltin.h
@@ -57,11 +57,7 @@
 #define fwrite(ptr, size, nmemb, file) outbin(ptr, (size) * (nmemb), file)
 #define fflush flushout
 #define INITARGS(argv)
-#define warnx(...) do {					\
-	out2fmt_flush("%s: ", commandname);		\
-	out2fmt_flush(__VA_ARGS__);			\
-	out2fmt_flush("\n");				\
-	} while (0)
+#define warnx warning
 #define errx(exitstatus, ...) error(__VA_ARGS__)
 
 #else
diff --git a/bin/sh/cd.c b/bin/sh/cd.c
index 068dfb74209f..041d6b4545c3 100644
--- a/bin/sh/cd.c
+++ b/bin/sh/cd.c
@@ -224,7 +224,7 @@ cdphysical(char *dest)
 	}
 	p = findcwd(NULL);
 	if (p == NULL)
-		out2fmt_flush("cd: warning: failed to get name of current directory\n");
+		warning("warning: failed to get name of current directory");
 	updatepwd(p);
 	INTON;
 	return (0);
diff --git a/bin/sh/error.c b/bin/sh/error.c
index beb75fad2d8f..c76a9dc65768 100644
--- a/bin/sh/error.c
+++ b/bin/sh/error.c
@@ -134,6 +134,26 @@ onint(void)
 }
 
 
+static void
+vwarning(const char *msg, va_list ap)
+{
+	if (commandname)
+		outfmt(out2, "%s: ", commandname);
+	doformat(out2, msg, ap);
+	out2fmt_flush("\n");
+}
+
+
+void
+warning(const char *msg, ...)
+{
+	va_list ap;
+	va_start(ap, msg);
+	vwarning(msg, ap);
+	va_end(ap);
+}
+
+
 /*
  * Exverror is called to raise the error exception.  If the first argument
  * is not NULL then error prints an error message using printf style
@@ -158,12 +178,8 @@ exverror(int cond, const char *msg, va_list ap)
 	else
 		TRACE(("exverror(%d, NULL) pid=%d\n", cond, getpid()));
 #endif
-	if (msg) {
-		if (commandname)
-			outfmt(out2, "%s: ", commandname);
-		doformat(out2, msg, ap);
-		out2c('\n');
-	}
+	if (msg)
+		vwarning(msg, ap);
 	flushall();
 	exraise(cond);
 }
diff --git a/bin/sh/error.h b/bin/sh/error.h
index 8b64fe6813d8..bf11c6750812 100644
--- a/bin/sh/error.h
+++ b/bin/sh/error.h
@@ -80,6 +80,7 @@ extern volatile sig_atomic_t intpending;
 
 void exraise(int) __dead2;
 void onint(void);
+void warning(const char *, ...) __printflike(1, 2);
 void error(const char *, ...) __printf0like(1, 2) __dead2;
 void exerror(int, const char *, ...) __printf0like(2, 3) __dead2;
 
diff --git a/bin/sh/trap.c b/bin/sh/trap.c
index 3a6803b9d90f..e673ef685a3d 100644
--- a/bin/sh/trap.c
+++ b/bin/sh/trap.c
@@ -185,7 +185,7 @@ trapcmd(int argc, char **argv)
 	}
 	while (*argv) {
 		if ((signo = sigstring_to_signum(*argv)) == -1) {
-			out2fmt_flush("trap: bad signal %s\n", *argv);
+			warning("bad signal %s", *argv);
 			errors = 1;
 		}
 		INTOFF;