title: Script in udev rule doesn't run
body: <p>I'm running Ubuntu 9.10 (Karmic Koala) on a laptop and would like NumLock to automatically toggle depending on whether my USB keyboard is plugged in (numlock on) or unplugged (numlock off).</p>
  
  <p>To accomplish this, I first installed the "numlockx" package. <code>numlockx on</code> and <code>numlockx off</code> works fine.</p>
  
  <p>To hook into the device system, I thought I'd use udev. I have looked at other questions on StackOverflow and read <a href="http://www.reactivated.net/writing_udev_rules.html" rel="nofollow noreferrer">"Writing udev rules"</a>. But I'm having trouble getting the udev rule to work.</p>
  
  <p>First, here's an example of the <code>dmesg</code> output:</p>
  
  <pre>
  [20906.985102] usb 3-2: new low speed USB device using uhci_hcd and address 6
  [20907.166403] usb 3-2: configuration #1 chosen from 1 choice
  [20907.192904] input: Microsoft Natural® Ergonomic Keyboard 4000 as /devices/pci0000:00/0000:00:1a.0/usb3/3-2/3-2:1.0/input/input20
  [20907.193100] microsoft 0003:045E:00DB.000B: input,hidraw1: USB HID v1.11 Keyboard [Microsoft Natural® Ergonomic Keyboard 4000] on usb-0000:00:1a.0-2/input0
  [20907.217810] input: Microsoft Natural® Ergonomic Keyboard 4000 as /devices/pci0000:00/0000:00:1a.0/usb3/3-2/3-2:1.1/input/input21
  [20907.217979] microsoft 0003:045E:00DB.000C: input,hidraw2: USB HID v1.11 Device [Microsoft Natural® Ergonomic Keyboard 4000] on usb-0000:00:1a.0-2/input1
  </pre>
  
  <p>I used <code>udevadm info</code> to gather the device info:</p>
  
  <pre>
  > udevadm info -a -p /devices/pci0000:00/0000:00:1a.0/usb3/3-2/3-2:1.1/input/input21
  
    looking at device '/devices/pci0000:00/0000:00:1a.0/usb3/3-2/3-2:1.1/input/input21':
      KERNEL=="input21"
      SUBSYSTEM=="input"
      DRIVER==""
      ATTR{phys}=="usb-0000:00:1a.0-2/input1"
      ATTR{uniq}==""
      ATTR{modalias}=="input:b0003v045Ep00DBe0111-e0,1,2,3,4,14,k71,72,73,74,75,77,79,7A,7B,7C,7D,7E,7F,80,81,82,83,84,85,86,87,88,89,8A,8B,8C,8E,90,96,98,9B,9C,9E,9F,A1,A3,A4,A5,A6,A7,A8,A9,AB,AC,AD,AE,B0,B1,B2,B3,B4,B5,B6,B8,B9,BA,BB,BC,BD,BE,BF,C0,C1,C2,CE,CF,D0,D1,D2,D5,D9,DB,DF,E2,E7,E8,E9,EA,EB,F0,100,162,166,16A,16E,178,179,17A,17B,17C,17D,17F,180,181,182,185,18C,18D,192,193,195,1A0,1A1,1A2,1A3,1A4,1A5,1A6,1A7,1A8,1A9,1AA,1AB,1AC,1AD,1AE,1B0,1B1,1B7,r6,a20,m4,lsfw"
  
    looking at parent device '/devices/pci0000:00/0000:00:1a.0/usb3/3-2/3-2:1.1':
      KERNELS=="3-2:1.1"
      SUBSYSTEMS=="usb"
      DRIVERS=="usbhid"
      ATTRS{bInterfaceNumber}=="01"
      ATTRS{bAlternateSetting}==" 0"
      ATTRS{bNumEndpoints}=="01"
      ATTRS{bInterfaceClass}=="03"
      ATTRS{bInterfaceSubClass}=="00"
      ATTRS{bInterfaceProtocol}=="00"
      ATTRS{modalias}=="usb:v045Ep00DBd0173dc00dsc00dp00ic03isc00ip00"
      ATTRS{supports_autosuspend}=="1"
  
    looking at parent device '/devices/pci0000:00/0000:00:1a.0/usb3/3-2':
      KERNELS=="3-2"
      SUBSYSTEMS=="usb"
      DRIVERS=="usb"
      ATTRS{configuration}==""
      ATTRS{bNumInterfaces}==" 2"
      ATTRS{bConfigurationValue}=="1"
      ATTRS{bmAttributes}=="a0"
      ATTRS{bMaxPower}=="100mA"
      ATTRS{urbnum}=="532"
      ATTRS{idVendor}=="045e"
      ATTRS{idProduct}=="00db"
      ATTRS{bcdDevice}=="0173"
      ATTRS{bDeviceClass}=="00"
      ATTRS{bDeviceSubClass}=="00"
      ATTRS{bDeviceProtocol}=="00"
      ATTRS{bNumConfigurations}=="1"
      ATTRS{bMaxPacketSize0}=="8"
      ATTRS{speed}=="1.5"
      ATTRS{busnum}=="3"
      ATTRS{devnum}=="6"
      ATTRS{version}==" 2.00"
      ATTRS{maxchild}=="0"
      ATTRS{quirks}=="0x0"
      ATTRS{authorized}=="1"
      ATTRS{manufacturer}=="Microsoft"
  
    looking at parent device '/devices/pci0000:00/0000:00:1a.0/usb3':
      KERNELS=="usb3"
      SUBSYSTEMS=="usb"
      DRIVERS=="usb"
      ATTRS{configuration}==""
      ATTRS{bNumInterfaces}==" 1"
      ATTRS{bConfigurationValue}=="1"
      ATTRS{bmAttributes}=="e0"
      ATTRS{bMaxPower}=="  0mA"
      ATTRS{urbnum}=="127"
      ATTRS{idVendor}=="1d6b"
      ATTRS{idProduct}=="0001"
      ATTRS{bcdDevice}=="0206"
      ATTRS{bDeviceClass}=="09"
      ATTRS{bDeviceSubClass}=="00"
      ATTRS{bDeviceProtocol}=="00"
      ATTRS{bNumConfigurations}=="1"
      ATTRS{bMaxPacketSize0}=="64"
      ATTRS{speed}=="12"
      ATTRS{busnum}=="3"
      ATTRS{devnum}=="1"
      ATTRS{version}==" 1.10"
      ATTRS{maxchild}=="2"
      ATTRS{quirks}=="0x0"
      ATTRS{authorized}=="1"
      ATTRS{manufacturer}=="Linux 2.6.31-16-generic uhci_hcd"
      ATTRS{product}=="UHCI Host Controller"
      ATTRS{serial}=="0000:00:1a.0"
      ATTRS{authorized_default}=="1"
  
    looking at parent device '/devices/pci0000:00/0000:00:1a.0':
      KERNELS=="0000:00:1a.0"
      SUBSYSTEMS=="pci"
      DRIVERS=="uhci_hcd"
      ATTRS{vendor}=="0x8086"
      ATTRS{device}=="0x2937"
      ATTRS{subsystem_vendor}=="0x1558"
      ATTRS{subsystem_device}=="0x0860"
      ATTRS{class}=="0x0c0300"
      ATTRS{irq}=="16"
      ATTRS{local_cpus}=="ff"
      ATTRS{local_cpulist}=="0-7"
      ATTRS{modalias}=="pci:v00008086d00002937sv00001558sd00000860bc0Csc03i00"
      ATTRS{broken_parity_status}=="0"
      ATTRS{msi_bus}==""
  
    looking at parent device '/devices/pci0000:00':
      KERNELS=="pci0000:00"
      SUBSYSTEMS==""
      DRIVERS==""
  </pre>
  
  <p>So I created a file called <code>/etc/udev/rules.d/usb-keyboard.rules</code>:</p>
  
  <pre>
  # Turn on NumLock when keyboard is plugged in.
  ACTION=="add", ATTRS{manufacturer}=="Microsoft", SUBSYSTEM=="input", RUN+="/usr/bin/numlockx on"
  
  # Turn off NumLock when keyboard is unplugged.
  ACTION=="remove", ATTRS{manufacturer}=="Microsoft", SUBSYSTEM=="input", RUN+="/usr/bin/numlockx off"
  </pre>
  
  <p>I have used <code>udevadm test</code> to verify that the rules are correct:</p>
  
  <pre>
  > udevadm test --action=add /devices/pci0000:00/0000:00:1a.0/usb3/3-2/3-2:1.1/input/input21
  run_command: calling: test
  udevadm_test: version 147
  
  [...]
  parse_file: reading '/etc/udev/rules.d/usb-keyboard.rules' as rules file
  udev_rules_new: rules use 180864 bytes tokens (15072 * 12 bytes), 31614 bytes buffer
  udev_rules_new: temporary index used 49760 bytes (2488 * 20 bytes)
  udev_device_new_from_syspath: device 0x28d7d80 has devpath '/devices/pci0000:00/0000:00:1a.0/usb3/3-2/3-2:1.1/input/input21'
  udev_rules_apply_to_event: RUN '/sbin/modprobe -b $env{MODALIAS}' /lib/udev/rules.d/80-drivers.rules:5
  udev_rules_apply_to_event: RUN 'socket:@/org/freedesktop/hal/udev_event' /lib/udev/rules.d/90-hal.rules:2
  udev_device_new_from_syspath: device 0x28d8560 has devpath '/devices/pci0000:00/0000:00:1a.0/usb3/3-2/3-2:1.1'
  udev_device_new_from_syspath: device 0x28d8708 has devpath '/devices/pci0000:00/0000:00:1a.0/usb3/3-2'
  udev_rules_apply_to_event: RUN '/usr/bin/numlockx on' /etc/udev/rules.d/usb-keyboard.rules:7
  udevadm_test: UDEV_LOG=6
  udevadm_test: DEVPATH=/devices/pci0000:00/0000:00:1a.0/usb3/3-2/3-2:1.1/input/input21
  udevadm_test: PRODUCT=3/45e/db/111
  udevadm_test: NAME="Microsoft Natural® Ergonomic Keyboard 4000"
  udevadm_test: PHYS="usb-0000:00:1a.0-2/input1"
  udevadm_test: UNIQ=""
  udevadm_test: EV==10001f
  udevadm_test: KEY==837fff 2c3027 bf004444 0 0 1 10f84 8a27c007 ff7f7bfa d9415fff febeffdf ffefffff ffffffff fffffffe
  udevadm_test: REL==40
  udevadm_test: ABS==1 0
  udevadm_test: MSC==10
  udevadm_test: MODALIAS=input:b0003v045Ep00DBe0111-e0,1,2,3,4,14,k71,72,73,74,75,77,79,7A,7B,7C,7D,7E,7F,80,81,82,83,84,85,86,87,88,89,8A,8B,8C,8E,90,96,98,9B,9C,9E,9F,A1,A3,A4,A5,A6,A7,A8,A9,AB,AC,AD,AE,B0,B1,B2,B3,B4,B5,B6,B8,B9,BA,BB,BC,BD,BE,BF,C0,C1,C2,CE,CF,D0,D1,D2,D5,D9,DB,DF,E2,E7,E8,E9,EA,EB,F0,100,162,166,16A,16E,178,179,17A,17B,17C,17D,17F,180,181,182,185,18C,18D,192,193,195,1A0,1A1,1A2,1A3,1A4,1A5,1A6,1A7,1A8,1A9,1AA,1AB,1AC,1AD,1AE,1B0,1B1,1B7,r6,a20,m4,lsfw
  udevadm_test: ACTION=add
  udevadm_test: SUBSYSTEM=input
  udevadm_test: run: '/sbin/modprobe -b input:b0003v045Ep00DBe0111-e0,1,2,3,4,14,k71,72,73,74,75,77,79,7A,7B,7C,7D,7E,7F,80,81,82,83,84,85,86,87,88,89,8A,8B,8C,8E,90,96,98,9B,9C,9E,9F,A1,A3,A4,A5,A6,A7,A8,A9,AB,AC,AD,AE,B0,B1,B2,B3,B4,B5,B6,B8,B9,BA,BB,BC,BD,BE,BF,C0,C1,C2,CE,CF,D0,D1,D2,D5,D9,DB,DF,E2,E7,E8,E9,EA,EB,F0,100,162,166,16A,16E,178,179,17A,17B,17C,17D,17F,180,181,182,185,18C,18D,192,193,195,1A0,1A1,1A2,1A3,1A4,1A5,1A6,1A7,1A8,1A9,1AA,1AB,1AC,1AD,1AE,1B0,1B1,1B7,r6,a20,m4,lsfw'
  udevadm_test: run: 'socket:@/org/freedesktop/hal/udev_event'
  udevadm_test: run: '/usr/bin/numlockx on'
  </pre>
  
  <p>And here's the "remove" test:</p>
  
  <pre>
  > udevadm test --action=remove /devices/pci0000:00/0000:00:1a.0/usb3/3-2/3-2:1.1/input/input21
  
  run_command: calling: test
  udevadm_test: version 147
  
  [...]
  parse_file: reading '/etc/udev/rules.d/usb-keyboard.rules' as rules file
  udev_rules_new: rules use 180864 bytes tokens (15072 * 12 bytes), 31614 bytes buffer
  udev_rules_new: temporary index used 49760 bytes (2488 * 20 bytes)
  udev_device_new_from_syspath: device 0xd2fd80 has devpath '/devices/pci0000:00/0000:00:1a.0/usb3/3-2/3-2:1.1/input/input21'
  udev_rules_apply_to_event: RUN 'socket:@/org/freedesktop/hal/udev_event' /lib/udev/rules.d/90-hal.rules:2
  udev_device_new_from_syspath: device 0xd2fff8 has devpath '/devices/pci0000:00/0000:00:1a.0/usb3/3-2/3-2:1.1'
  udev_device_new_from_syspath: device 0xd30690 has devpath '/devices/pci0000:00/0000:00:1a.0/usb3/3-2'
  udev_rules_apply_to_event: RUN '/usr/bin/numlockx off' /etc/udev/rules.d/usb-keyboard.rules:10
  udevadm_test: UDEV_LOG=6
  udevadm_test: DEVPATH=/devices/pci0000:00/0000:00:1a.0/usb3/3-2/3-2:1.1/input/input21
  udevadm_test: PRODUCT=3/45e/db/111
  udevadm_test: NAME="Microsoft Natural® Ergonomic Keyboard 4000"
  udevadm_test: PHYS="usb-0000:00:1a.0-2/input1"
  udevadm_test: UNIQ=""
  udevadm_test: EV==10001f
  udevadm_test: KEY==837fff 2c3027 bf004444 0 0 1 10f84 8a27c007 ff7f7bfa d9415fff febeffdf ffefffff ffffffff fffffffe
  udevadm_test: REL==40
  udevadm_test: ABS==1 0
  udevadm_test: MSC==10
  udevadm_test: MODALIAS=input:b0003v045Ep00DBe0111-e0,1,2,3,4,14,k71,72,73,74,75,77,79,7A,7B,7C,7D,7E,7F,80,81,82,83,84,85,86,87,88,89,8A,8B,8C,8E,90,96,98,9B,9C,9E,9F,A1,A3,A4,A5,A6,A7,A8,A9,AB,AC,AD,AE,B0,B1,B2,B3,B4,B5,B6,B8,B9,BA,BB,BC,BD,BE,BF,C0,C1,C2,CE,CF,D0,D1,D2,D5,D9,DB,DF,E2,E7,E8,E9,EA,EB,F0,100,162,166,16A,16E,178,179,17A,17B,17C,17D,17F,180,181,182,185,18C,18D,192,193,195,1A0,1A1,1A2,1A3,1A4,1A5,1A6,1A7,1A8,1A9,1AA,1AB,1AC,1AD,1AE,1B0,1B1,1B7,r6,a20,m4,lsfw
  udevadm_test: ACTION=remove
  udevadm_test: SUBSYSTEM=input
  udevadm_test: run: 'socket:@/org/freedesktop/hal/udev_event'
  udevadm_test: run: '/usr/bin/numlockx off'
  </pre>
  
  <p>The problem is that when the keyboard is plugged in or unplugged, the NumLock status doesn't change. I have tried restarting the udev service, with no luck. Are my udev rules wrong? Am I going about this the wrong way?</p>