Index: contrib/netbsd-tests/usr.bin/grep/t_grep_freebsd.sh
===================================================================
--- /dev/null
+++ contrib/netbsd-tests/usr.bin/grep/t_grep_freebsd.sh
@@ -0,0 +1,60 @@
+# $FreeBSD$
+#
+# Copyright (c) 2017 Kyle Evans <kevans91@ksu.edu>
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+# ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+# PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+
+atf_test_case grep_r_implied
+grep_r_implied_head()
+{
+	atf_set "timeout" "5"
+}
+grep_r_implied_body()
+{
+	(cd "$(atf_get_srcdir)" && grep -r --exclude="*.out" -e "test" .) > d_grep_r_implied.out
+
+	atf_expect_timeout "grep -r implying working directory if none specified is a BSD grep feature"
+	atf_check -s exit:0 -x \
+	    "(cd $(atf_get_srcdir) && grep -r --exclude=\"*.out\" -e "test") | diff d_grep_r_implied.out -"
+}
+
+atf_test_case rgrep
+rgrep_head()
+{
+	atf_set "timeout" "5"
+}
+rgrep_body()
+{
+	atf_expect_fail "rgrep is a BSD grep feature and not installed with GNU grep"
+	(cd "$(atf_get_srcdir)" && rgrep --exclude="*.out" -e "test" .) > d_grep_r_implied.out
+
+	atf_check -s exit:0 -x \
+	    "(cd $(atf_get_srcdir) && rgrep --exclude=\"*.out\" -e "test") | diff d_grep_r_implied.out -"
+}
+
+atf_init_test_cases()
+{
+	atf_add_test_case grep_r_implied
+	atf_add_test_case rgrep
+}
Index: usr.bin/grep/grep.c
===================================================================
--- usr.bin/grep/grep.c
+++ usr.bin/grep/grep.c
@@ -732,7 +732,7 @@
 	if ((aargc == 0 || aargc == 1) && !Hflag)
 		hflag = true;
 
-	if (aargc == 0)
+	if (aargc == 0 && dirbehave != DIR_RECURSE)
 		exit(!procfile("-"));
 
 	if (dirbehave == DIR_RECURSE)
Index: usr.bin/grep/tests/Makefile
===================================================================
--- usr.bin/grep/tests/Makefile
+++ usr.bin/grep/tests/Makefile
@@ -2,7 +2,7 @@
 
 PACKAGE=	tests
 
-NETBSD_ATF_TESTS_SH=	grep_test
+NETBSD_ATF_TESTS_SH=	grep_test grep_freebsd_test
 
 ${PACKAGE}FILES+=		d_basic.out
 ${PACKAGE}FILES+=		d_begin_end_a.out
Index: usr.bin/grep/util.c
===================================================================
--- usr.bin/grep/util.c
+++ usr.bin/grep/util.c
@@ -111,6 +111,7 @@
 	FTSENT *p;
 	int c, fts_flags;
 	bool ok;
+	const char *wd[] = { ".", NULL };
 
 	c = fts_flags = 0;
 
@@ -128,7 +129,9 @@
 
 	fts_flags |= FTS_NOSTAT | FTS_NOCHDIR;
 
-	if (!(fts = fts_open(argv, fts_flags, NULL)))
+	fts = fts_open((argv[0] == NULL) ?
+	    __DECONST(char * const *, wd) : argv, fts_flags, NULL);
+	if (fts == NULL)
 		err(2, "fts_open");
 	while ((p = fts_read(fts)) != NULL) {
 		switch (p->fts_info) {