diff --git a/roles/usb_lib/files/usbmount/usbmount b/roles/usb_lib/files/usbmount/usbmount
index d280eb354..b4572acc4 100644
--- a/roles/usb_lib/files/usbmount/usbmount
+++ b/roles/usb_lib/files/usbmount/usbmount
@@ -24,8 +24,8 @@ exec > /dev/null 2>&1
 # Log a string via the syslog facility.
 log()
 {
-    if [ $1 != debug ] || expr "$VERBOSE" : "[yY]" > /dev/null; then
-	logger -p user.$1 -t "usbmount[$$]" -- "$2"
+    if [ "$1" != debug ] || expr "$VERBOSE" : "[yY]" > /dev/null; then
+	logger -p user."$1" -t "usbmount[$$]" -- "$2"
     fi
 }
 
@@ -90,12 +90,12 @@ if [ "$1" = add ]; then
     # Grab device information from device and "divide it"
     #   FIXME: improvement: implement mounting by label (notice that labels
     #   can contain spaces, which makes things a little bit less comfortable).
-    DEVINFO=$(/sbin/blkid -p $DEVNAME)
+    DEVINFO=$(/sbin/blkid -p "$DEVNAME")
     FSTYPE=$(echo "$DEVINFO" | sed 's/.*[[:blank:]]TYPE="\([^"]*\)".*/\1/g; s/[[:blank:]]*//g;')
     UUID=$(echo "$DEVINFO"   | sed 's/.*[[:blank:]]UUID="\([^"]*\)".*/\1/g; s/[[:blank:]]*//g;')
     USAGE=$(echo "$DEVINFO"  | sed 's/.*[[:blank:]]USAGE="\([^"]*\)".*/\1/g; s/[[:blank:]]*//g;')
 
-    if ! echo $USAGE | egrep -q "(filesystem|disklabel)"; then
+    if ! echo "$USAGE" | grep -Eq "(filesystem|disklabel)"; then
         log debug "/$DEVNAME does not contain a filesystem or disklabel"
         lockfile-remove /var/run/usbmount/.mount
         exit
@@ -109,26 +109,26 @@ if [ "$1" = add ]; then
     BOOT_DEV=$(/usr/bin/findmnt -no source /boot)
     log debug "BOOT_DEV $BOOT_DEV"
 
-    if [ $BOOTFW_DEV = /$DEVNAME ]; then
-        log debug "skipping BOOTFS_DEV $BOOTFS_DEV mounted at /boot/firmware"
+    if [ "$BOOTFW_DEV" = /"$DEVNAME" ]; then
+        log debug "skipping BOOTFW_DEV $BOOTFW_DEV mounted at /boot/firmware"
         lockfile-remove /var/run/usbmount/.mount
         exit
-    elif [ $ROOT_DEV = /$DEVNAME ]; then
+    elif [ "$ROOT_DEV" = /"$DEVNAME" ]; then
         log debug "skipping ROOT_DEV $ROOT_DEV mounted at /"
         lockfile-remove /var/run/usbmount/.mount
         exit
-    elif [ $BOOT_DEV = /$DEVNAME ]; then
+    elif [ "$BOOT_DEV" = /"$DEVNAME" ]; then
         log debug "skipping BOOT_DEV $BOOT_DEV mount as /boot"
         lockfile-remove /var/run/usbmount/.mount
         exit
     fi
 
     # Try to use specifications in /etc/fstab to skip.
-    if egrep -q "^[[:blank:]]*$DEVNAME" /etc/fstab; then
+    if grep -Eq "^[[:blank:]]*$DEVNAME" /etc/fstab; then
         log debug "skipping /$DEVNAME exit"
         lockfile-remove /var/run/usbmount/.mount
         exit
-    elif grep -q "^[[:blank:]]*UUID=$UUID" /etc/fstab; then
+    elif grep -Eq "^[[:blank:]]*UUID=$UUID" /etc/fstab; then
         log debug "skipping $UUID"
         lockfile-remove /var/run/usbmount/.mount
         exit
@@ -166,25 +166,25 @@ if [ "$1" = add ]; then
                 # Determine vendor and model.
                 vendor=
                 if [ -r "/sys$DEVPATH/device/vendor" ]; then
-                    vendor="`cat \"/sys$DEVPATH/device/vendor\"`"
+                    vendor="$(cat \"/sys"$DEVPATH"/device/vendor\")"
                 elif [ -r "/sys$DEVPATH/../device/vendor" ]; then
-                    vendor="`cat \"/sys$DEVPATH/../device/vendor\"`"
+                    vendor="$(cat \"/sys"$DEVPATH"/../device/vendor\")"
                 elif [ -r "/sys$DEVPATH/device/../manufacturer" ]; then
-                    vendor="`cat \"/sys$DEVPATH/device/../manufacturer\"`"
+                    vendor="$(cat \"/sys"$DEVPATH"/device/../manufacturer\")"
                 elif [ -r "/sys$DEVPATH/../device/../manufacturer" ]; then
-                    vendor="`cat \"/sys$DEVPATH/../device/../manufacturer\"`"
+                    vendor="$(cat \"/sys"$DEVPATH"/../device/../manufacturer\")"
                 fi
                 vendor="$(echo "$vendor" | sed 's/^[[:blank:]]\+//; s/[[:blank:]]\+$//')"
 
                 model=
                 if [ -r "/sys$DEVPATH/device/model" ]; then
-                    model="`cat \"/sys$DEVPATH/device/model\"`"
+                    model="$(cat \"/sys"$DEVPATH"/device/model\")"
                 elif [ -r "/sys$DEVPATH/../device/model" ]; then
-                    model="`cat \"/sys$DEVPATH/../device/model\"`"
+                    model="$(cat \"/sys"$DEVPATH"/../device/model\")"
                 elif [ -r "/sys$DEVPATH/device/../product" ]; then
-                    model="`cat \"/sys$DEVPATH/device/../product\"`"
+                    model="$(cat \"/sys"$DEVPATH"/device/../product\")"
                 elif [ -r "/sys$DEVPATH/../device/../product" ]; then
-                    model="`cat \"/sys$DEVPATH/../device/../product\"`"
+                    model="$(cat \"/sys"$DEVPATH"/../device/../product\")"
                 fi
                 model="$(echo "$model" | sed 's/^[[:blank:]]\+//; s/[[:blank:]]\+$//')"
 
@@ -208,7 +208,7 @@ elif [ "$1" = remove ]; then
 
     # A block or partition device has been removed.
     # Test if it is mounted.
-    while read device mountpoint fstype remainder; do
+    while read -r device mountpoint fstype; do
     if [ "/$DEVNAME" = "$device" ]; then
         log debug "umount device is $device"
         # If the mountpoint and filesystem type are maintained by