diff --git a/scripts/fsadm.sh b/scripts/fsadm.sh
index a09b91534..28ca6709f 100755
--- a/scripts/fsadm.sh
+++ b/scripts/fsadm.sh
@@ -311,10 +311,10 @@ detect_mounted_with_proc_self_mountinfo() {
 # device (which could have been renamed).
 # We need to visit every mount point and check it's major minor
 detect_mounted_with_proc_mounts() {
-	MOUNTED=$("$GREP" "^$VOLUME[ \t]" "$PROCMOUNTS")
+	MOUNTED=$("$GREP" "^$VOLUME[ \\t]" "$PROCMOUNTS")
 
 	# for empty string try again with real volume name
-	test -z "$MOUNTED" && MOUNTED=$("$GREP" "^$RVOLUME[ \t]" "$PROCMOUNTS")
+	test -z "$MOUNTED" && MOUNTED=$("$GREP" "^$RVOLUME[ \\t]" "$PROCMOUNTS")
 
 	MOUNTDEV=$(echo -n -e "${MOUNTED%% *}")
 	# cut device name prefix and trim everything past mountpoint
@@ -325,8 +325,8 @@ detect_mounted_with_proc_mounts() {
 	# for systems with different device names - check also mount output
 	if test -z "$MOUNTED" ; then
 		# will not work with spaces in paths
-		MOUNTED=$(LC_ALL=C "$MOUNT" | "$GREP" "^$VOLUME[ \t]")
-		test -z "$MOUNTED" && MOUNTED=$(LC_ALL=C "$MOUNT" | "$GREP" "^$RVOLUME[ \t]")
+		MOUNTED=$(LC_ALL=C "$MOUNT" | "$GREP" "^$VOLUME[ \\t]")
+		test -z "$MOUNTED" && MOUNTED=$(LC_ALL=C "$MOUNT" | "$GREP" "^$RVOLUME[ \\t]")
 		MOUNTDEV=${MOUNTED%% on *}
 		MOUNTED=${MOUNTED##* on }
 		MOUNTED=${MOUNTED% type *} # allow type in the mount name