diff --git a/lsusb b/lsusb
index 0890c2a..0ab71cd 100755
--- a/lsusb
+++ b/lsusb
@@ -4,8 +4,8 @@
 #
 # Disclaimer: usage info and functionality from lsusb under Linux
 
-verbose () { system_profiler SPUSBDataType; }
-version () { echo "lsusb for Mac OS X 007"; }
+verbose () { system_profiler SPUSBDataType 2>/dev/null; }
+version () { echo "lsusb for Mac OS X 008"; }
 help ()  {
   cat >&2 <<EOM
 $(usage)
@@ -25,34 +25,41 @@ EOM
 }
 usage () { echo "Usage: $(basename "$0") [options]..."; }
 
+unknown_dev_num=127
 parse ()  {
 	# Get the name of the device, it is the first line that ends with a ':'
 	# Trim the string at the end
-	name=`echo "$device" | head -2 | egrep ":$"  | sed -e 's/^ *//g' -e 's/ *:$//g'`
+	name=`echo "$device" | head -2 | grep ":$"  | sed -e 's/^ *//g' -e 's/ *:$//g'`
 
 	# Get the speed
-	speed=`echo "$device" | egrep "Speed: " | awk -F':' '{print $2}' | sed 's/^ *[^0-9]*//g; s/ *$//; s/b\/sec$//; s/ //g'`
+	speed=`echo "$device" | grep "Speed: " | awk -F':' '{print $2}' | sed 's/^ *[^0-9]*//g; s/ *$//; s/b\/sec$//; s/ //g'`
 
 	# Get the PID, trim at the end
-	PID=`echo "$device" | egrep "Product ID" | awk -F':' '{print $2}' | sed -e 's/0x//; s/^ *//g' -e 's/ *$//g'`
+	PID=`echo "$device" | grep "Product ID" | awk -F':' '{print $2}' | sed -e 's/0x//; s/^ *//g' -e 's/ *$//g'`
 
 	# Get the VID string, trim at the end
-	VID_all=`echo "$device" | egrep "Vendor ID" | awk -F':' '{print $2}' | sed -e 's/0x//; s/^ *//g' -e 's/ *$//g'`
+	VID_all=`echo "$device" | grep "Vendor ID" | awk -F':' '{print $2}' | sed -e 's/0x//; s/^ *//g' -e 's/ *$//g'`
 	# Get the VID
 	VID=`echo "$VID_all" | awk -F ' ' '{print $1}' | sed 's/^ *//; s/ *$//'`
 	# Get the manufacturer string
 	manufacturer=`echo "$VID_all" | cut -d ' ' -f 2- | sed 's/^ *//; s/ *$//'`
 
 	# Get the Location Id
-	location=`echo "$device" | egrep "Location ID" | sed -e 's/Location ID://; s/^ *//g; s/ *$//g;'`
+	location=`echo "$device" | grep "Location ID" | sed -e 's/Location ID://; s/^ *//g; s/ *$//g;'`
 
 	# Get the bus number. It's the first two hex digits of the Location ID.
 	# We'll convert to decimal later
 	bus_num=`echo "$location" |  sed -e 's/^..\(..\).*/\1/;'`
+	if [[ -z $bus_num ]]; then
+		bus_num="00"
+	fi
 
 	# Get the device number. It's after the '/' in the Location ID, already decimal.
 	device_num=`echo "$location" | awk -F'/' '{print $2}'`
-	device_num=`printf "%0*d" 3 "$device_num"`
+	if [[ -z $device_num ]]; then
+		device_num=$((unknown_dev_num--))
+	fi
+	device_num=`printf "%03d" "$device_num"`
 
 	# Strip off the excess from LocationID for sorting tree.
 	locationID=`echo "$location" | awk -F'/' '{print $1}'`
@@ -64,7 +71,10 @@ parse ()  {
 		fi
 
 		# Get the bus number, in hexadecimal. We'll convert to decimal later.
-		bus_num=`echo "$device" | egrep "Bus Number" | sed -e 's/Bus Number://' -e 's/0x//; s/^ *//g' -e 's/ *$//g'`
+		bus_num=`echo "$device" | grep "Bus Number" | sed -e 's/Bus Number://' -e 's/0x//; s/^ *//g' -e 's/ *$//g'`
+		if [[ -z $bus_num ]]; then
+			bus_num="00"
+		fi
 
 		# Create a fake Location ID for sorting purposes, following the model.
 		locationID="0x${bus_num}000000"
@@ -77,7 +87,7 @@ parse ()  {
 		manufacturer="(Apple Inc.)"
 
 		# The PID depends on the speed of the hub, which we deduce from the controller driver.
-		PID=`echo "$device" | egrep "Controller Driver" | awk -F':' '{print $2}' | sed -e 's/0x//; s/^ *//g' -e 's/ *$//g; s/.*\(....\)$/\1/'`
+		PID=`echo "$device" | grep "Controller Driver" | awk -F':' '{print $2}' | sed -e 's/0x//; s/^ *//g' -e 's/ *$//g; s/.*\(....\)$/\1/'`
 	  	case "$PID" in
 			OHCI) PID="8005"; name="OHCI Root Hub Simulation"; speed="12M" ;;
 			EHCI) PID="8006"; name="EHCI Root Hub Simulation"; speed="480M" ;;
@@ -86,8 +96,7 @@ parse ()  {
 	fi
 
 	# Convert bus number from hexadecimal to decimal.
-	bus_num=`echo "$((16#$bus_num))"`
-        bus_num=`printf "%0*d" 3 "$bus_num"`
+	bus_num=$(printf "%03d" "0x0$bus_num")
 
 	# Strip the parentheses from manufacturer name unless so specified.
 	if [ -z "$parens" ]; then	
@@ -96,7 +105,7 @@ parse ()  {
 
 	# Include serial number only if available.
 	serial_str=""
-	serial_number=`echo "$device" | egrep "Serial Number" | sed 's/Serial Number: //; s/^ *//g; s/ *$//g'`
+	serial_number=`echo "$device" | grep "Serial Number" | sed 's/Serial Number: //; s/^ *//g; s/ *$//g'`
 	if [ -n "$serial_number" ]; then
 		serial_str=" Serial: ""$serial_number"
 	fi
@@ -110,7 +119,7 @@ parse ()  {
 	# Filter by VID/PID if given as input argument.
 	if [ -n "$vid_pid" ]; then
 	# Convert input vid to lower case.
-	   if [ -n "$(echo "$vid_pid" | egrep ':')" ]; then
+	   if [ -n "$(echo "$vid_pid" | grep ':')" ]; then
 		arg_vid=`echo "$vid_pid" | awk -F':' '{print $1}' | sed 's/^0x//' | tr '[A-Z]' '[a-z]'`
 		if [ -n "$arg_vid" ]; then
 			if [ $((16#$arg_vid)) -ne $((16#$VID)) ]; then
@@ -132,7 +141,7 @@ parse ()  {
 
 	# Filter by BUS/DEV if given as input argument.
 	if [ -n "$bus_dev" ]; then
-	    if [ -n "$(echo "$bus_dev" | egrep ':')" ]; then
+	    if [ -n "$(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 "$arg_bus" ]; then
@@ -150,7 +159,7 @@ parse ()  {
 	    fi
 	fi
 	# Special case: no colon after -s means device-only.
-	if [ -z "$(echo "$bus_dev" | egrep ':')" ]; then
+	if [ -z "$(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
@@ -206,12 +215,20 @@ buildtreeline () {
 	treeline="${locationID}${spaces}Bus ""${bus_num}"".Dev ""${device_num}"": ""${name}"", ""${speed}"
 }
 
+get_devices() {
+	<<<"$rawlog" sed -e '/:$/i\
+#'
+}
+
+get_buses() {
+	<<<"$rawlog" awk -v first=1 '/Bus:$/ { flag = 1; if (first == 1) { first = 0 } else { print "#" }; print; next }; /:$/ && flag == 1 { flag = 0 }; flag'
+}
+
 tree () {
 	setup
 	treeflag="yes"
 
-	devices=`echo "$rawlog" | egrep -B 2 -A 6 "Product ID" | sed 's/^--/#/'`
-	for device in $devices
+	for device in $(get_devices)
 	do
 		# Skip null device lines
 		if [ "${#device}" -ne 1 ]; then
@@ -221,8 +238,7 @@ tree () {
 		fi
 	done
 
-	buses=`echo "$rawlog" | egrep -A 7 "Bus:" | sed 's/^--/#/'`
-	for device in $buses
+	for device in $(get_buses)
 	do
 		parse
 		buildtreeline
@@ -282,9 +298,8 @@ setup
 # with the '#' symbol in case other parameters that contain a dash
 # will not be interfered
 
-devices=`echo "$rawlog" | egrep -B 2 -A 6 "Product ID" | sed 's/^--/#/'`
 # Iterate over each entry
-for device in $devices
+for device in $(get_devices)
 do
 	parse
 	if [ $? -eq 0 ]; then
@@ -293,8 +308,8 @@ do
 	fi
 done
 
-buses=`echo "$rawlog" | egrep -A 7 "Bus:" | sed 's/^--/#/'`
-for device in $buses
+echo "Buses:"
+for device in $(get_buses)
 do
 	parse
 	if [ $? -eq 0 ]; then