diff --git a/lsusb b/lsusb
index 93f0002..eb8e5fe 100755
--- a/lsusb
+++ b/lsusb
@@ -10,10 +10,13 @@ shopt -s extglob
 
 verbose() {
   system_profiler SPUSBDataType 2>/dev/null
+
+  # Restore the IFS and exit
+  cleanup
 }
 
 version() {
-  echo "lsusb for macOS 1.1.2"
+  echo "lsusb for macOS 1.1.3"
 }
 
 help() {
@@ -32,6 +35,9 @@ List USB devices
   -V  Show version of program
   -h  Show usage and help
 EOM
+
+# Restore the IFS and exit
+cleanup
 }
 
 usage() {
@@ -121,7 +127,7 @@ parse() {
     esac
   fi
 
-  if [ ${#bus_num} -ne 0 ]; then
+  if [ ${#bus_num} != 0 ]; then
     # Convert bus number from hexadecimal to decimal.
     bus_num=$(printf "%03d" "0x0$bus_num")
   else
@@ -149,51 +155,55 @@ parse() {
   # Filter by VID/PID if given as input argument.
   if [ -n "$vid_pid" ]; then
     # Convert input vid to lower case.
+    # shellcheck disable=SC2143
     if [ -n "$(echo "$vid_pid" | grep ':')" ]; then
       arg_vid=$(echo "$vid_pid" | awk -F':' '{print $1}' | sed 's/^0x//' | tr '[:upper:]' '[:lower:]')
       if [ -n "$arg_vid" ]; then
-        if [ $((16#$arg_vid)) -ne $((16#$VID)) ]; then
+        if [ $((16#$arg_vid)) != $((16#$VID)) ]; then
           return 1
         fi
       fi
       arg_pid=$(echo "$vid_pid" | awk -F':' '{print $2}' | sed 's/^0x//' | tr '[:upper:]' '[:lower:]')
       if [ -n "$arg_pid" ]; then
-        if [ $((16#$arg_pid)) -ne $((16#$PID)) ]; then
+        if [ $((16#$arg_pid)) != $((16#$PID)) ]; then
           return 1
         fi
       fi
     else
       # Missing a colon is a syntax error in -d option
       help
+      # shellcheck disable=SC2317
       exit 1
     fi
   fi
 
   # Filter by BUS/DEV if given as input argument.
   if [ -n "$bus_dev" ]; then
+    # shellcheck disable=SC2143
     if [ -n "$(echo "$bus_dev" | grep ':')" ]; then
       # Convert input bus to lower case
       arg_bus=$(echo "$bus_dev" | awk -F':' '{print $1}' | sed 's/^ *//; s/ *$//')
       if [ -n "$arg_bus" ]; then
-        if [ "$arg_bus" -ne "$bus_num" ]; then
+        if [ "$arg_bus" != "$bus_num" ]; then
           return 1
         fi
       fi
       # Strip leading and trailing spaces from argument.
       arg_dev=$(echo "$bus_dev" | awk -F':' '{print $2}' | sed 's/^ *//; s/ *$//')
       if [ -n "$arg_dev" ]; then
-        if [ "$arg_dev" -ne "$device_num" ]; then
+        if [ "$arg_dev" != "$device_num" ]; then
           return 1
         fi
       fi
     fi
   fi
   # Special case: no colon after -s means device-only.
+  # shellcheck disable=SC2143
   if [ -z "$(echo "$bus_dev" | grep ':')" ]; then
     # Strip leading and trailing spaces from argument.
     arg_dev=$(echo "$bus_dev" | sed 's/^ *//; s/ *$//')
     if [ -n "$arg_dev" ]; then
-      if [ "$arg_dev" -ne "$device_num" ]; then
+      if [ "$arg_dev" != "$device_num" ]; then
         return 1
       fi
     fi
@@ -222,6 +232,7 @@ setup() {
 
 cleanup() {
   IFS=$OIFS
+  # shellcheck disable=SC2086
   exit $exitcode
 }
 
@@ -260,7 +271,7 @@ tree() {
 
   for device in $(get_devices); do
     # Skip null device lines
-    if [ "${#device}" -ne 1 ]; then
+    if [ "${#device}" != 1 ]; then
       parse
       buildtreeline
       treedata="$treedata""${treeline}"$'\n'