diff --git a/usr.sbin/sysrc/sysrc b/usr.sbin/sysrc/sysrc
index 01ea31f8115a..70676e2e8683 100644
--- a/usr.sbin/sysrc/sysrc
+++ b/usr.sbin/sysrc/sysrc
@@ -45,6 +45,7 @@ SYSRC_VERSION="6.0 Nov-07,2013"
 #
 # Options
 #
+CHECK_ONLY=
 DELETE=
 DESCRIBE=
 IGNORE_UNKNOWNS=
@@ -100,6 +101,8 @@ help()
 	      "Dump a list of all non-default configuration variables."
 	f_err "$optfmt" "-A" \
 	      "Dump a list of all configuration variables (incl. defaults)."
+	f_err "$optfmt" "-c" \
+	      "Check. Return success if no changes needed, else error."
 	f_err "$optfmt" "-d" \
 	      "Print a description of the given variable."
 	f_err "$optfmt" "-D" \
@@ -222,10 +225,11 @@ jail_depend()
 #
 # Process command-line flags
 #
-while getopts aAdDef:Fhij:nNqR:vxX flag; do
+while getopts aAcdDef:Fhij:nNqR:vxX flag; do
 	case "$flag" in
 	a) SHOW_ALL=${SHOW_ALL:-1};;
 	A) SHOW_ALL=2;;
+	c) CHECK_ONLY=1;;
 	d) DESCRIBE=1;;
 	D) RC_CONFS=;;
 	e) SHOW_EQUALS=1;;
@@ -286,6 +290,12 @@ if [ "$DELETE" -a "$SHOW_ALL" ]; then
 	[ "$DELETE" = "2" ] || die "$errmsg"
 fi
 
+#
+# Pre-flight for `-c' command-line option
+#
+[ "$CHECK_ONLY" -a "$SHOW_ALL" ] &&
+	die "$pgm: \`-c' option incompatible with \`-a'/\`-A' options"
+
 #
 # Process `-e', `-n', and `-N' command-line options
 #
@@ -312,6 +322,7 @@ if [ "$JAIL" -o "$ROOTDIR" ]; then
 		$( [ "$DELETE" = "2" ] && echo \ -X )
 		$( [ "$SHOW_ALL" = "1" ] && echo \ -a )
 		$( [ "$SHOW_ALL" = "2" ] && echo \ -A )
+		${CHECK_ONLY:+-c}
 		${DESCRIBE:+-d}
 		${SHOW_EQUALS:+-e}
 		${IGNORE_UNKNOWNS:+-i}
@@ -422,7 +433,7 @@ if [ "$SHOW_ALL" ]; then
 		EXCEPT="IFS|EXCEPT|PATH|RC_DEFAULTS|OPTIND|DESCRIBE|SEP"
 		EXCEPT="$EXCEPT|DELETE|SHOW_ALL|SHOW_EQUALS|SHOW_NAME"
 		EXCEPT="$EXCEPT|SHOW_VALUE|SHOW_FILE|SYSRC_VERBOSE|RC_CONFS"
-		EXCEPT="$EXCEPT|pgm|SUCCESS|FAILURE"
+		EXCEPT="$EXCEPT|pgm|SUCCESS|FAILURE|CHECK_ONLY"
 		EXCEPT="$EXCEPT|f_sysrc_desc_awk|f_sysrc_delete_awk"
 
 		#
@@ -515,6 +526,7 @@ fi
 #
 # Process command-line arguments
 #
+costatus=$SUCCESS
 while [ $# -gt 0 ]; do
 	NAME="${1%%=*}"
 
@@ -528,7 +540,7 @@ while [ $# -gt 0 ]; do
 		# first describe, then attempt to set
 		#
 
-		if [ "$SYSRC_VERBOSE" ]; then
+		if [ "$SYSRC_VERBOSE" -a ! "$CHECK_ONLY" ]; then
 			file=$( f_sysrc_find "$NAME" )
 			[ "$file" = "$RC_DEFAULTS" -o ! "$file" ] && \
 				file=$( f_sysrc_get 'rc_conf_files%%[$IFS]*' )
@@ -545,6 +557,20 @@ while [ $# -gt 0 ]; do
 			continue
 		fi
 
+		#
+		# If `-c' is passed, simply compare and move on
+		#
+		if [ "$CHECK_ONLY" ]; then
+			if ! IGNORED=$( f_sysrc_get "$NAME?" ); then
+				costatus=$FAILURE
+			else
+				value=$( f_sysrc_get "$NAME" )
+				[ "$value" = "${1#*=}" ] || costatus=$FAILURE
+			fi
+			shift 1
+			continue
+		fi
+
 		#
 		# If `-N' is passed, simplify the output
 		#
@@ -572,9 +598,16 @@ while [ $# -gt 0 ]; do
 		fi
 		;;
 	*)
-		if ! IGNORED="$( f_sysrc_get "$NAME?" )"; then
-			[ "$IGNORE_UNKNOWNS" ] \
-				|| echo "$pgm: unknown variable '$NAME'"
+		if ! IGNORED=$( f_sysrc_get "$NAME?" ); then
+			[ "$IGNORE_UNKNOWNS" ] ||
+				echo "$pgm: unknown variable '$NAME'"
+			shift 1
+			costatus=$FAILURE
+			continue
+		fi
+
+		# The above check told us what we needed for `-c'
+		if [ "$CHECK_ONLY" ]; then
 			shift 1
 			continue
 		fi
@@ -623,3 +656,5 @@ while [ $# -gt 0 ]; do
 	esac
 	shift 1
 done
+
+[ ! "$CHECK_ONLY" ] || exit $costatus
diff --git a/usr.sbin/sysrc/sysrc.8 b/usr.sbin/sysrc/sysrc.8
index 0a4aace2e861..6d53e19665cd 100644
--- a/usr.sbin/sysrc/sysrc.8
+++ b/usr.sbin/sysrc/sysrc.8
@@ -32,13 +32,13 @@
 .Nd safely edit system rc files
 .Sh SYNOPSIS
 .Nm
-.Op Fl dDeFhinNqvx
+.Op Fl cdDeFhinNqvx
 .Op Fl f Ar file
 .Op Fl j Ar jail | Fl R Ar dir
 .Ar name Ns Op = Ns Ar value
 .Ar ...
 .Nm
-.Op Fl dDeFhinNqvx
+.Op Fl cdDeFhinNqvx
 .Op Fl f Ar file
 .Op Fl j Ar jail | Fl R Ar dir
 .Fl a | A
@@ -57,6 +57,12 @@ Dump a list of all non-default configuration variables.
 .It Fl A
 Dump a list of all configuration variables
 .Pq incl. defaults .
+.It Fl c
+Check if the value will change when assigning a new value.
+If verbose
+.Pq see Dq Fl v
+prints a message stating whether a change would occur.
+Exits with success if no change is necessary, else returns error status.
 .It Fl d
 Print a description of the given variable.
 .It Fl D