Get ambient light sensor value from ioreg I'm using the ioreg command line tool to try and read sensor information available on my computer (iMac).  Particularly, I'd like to read the current value of the ambient light sensor.  So far, I have been able to retrieve some general information regarding the sensor via ioreg -f -b -r -c 'AppleLMUController'. But the value is not there:

+-o AppleLMUController  &lt;class AppleLMUController, id 0x1000002d8, registered, matched, active, busy 0 (0 ms), retain 7&gt;
{
  "IOProbeScore" = 0
  "CFBundleIdentifier" = "com.apple.driver.AppleSMCLMU"
  "IOProviderClass" = "IOService"
  "IOClass" = "AppleLMUController"
  "IOMatchCategory" = "IODefaultMatchCategory"
  "IOCFPlugInTypes" = {"0516B563-B15B-11DA-96EB-0014519758EF"="AppleSMCLMU.kext/Contents/PlugIns/AmbientLightSensorHID.plugin"}
  "IOGeneralInterest" = "IOCommand is not serializable"
  "IONameMatch" = "ACPI0008"
  "IOPowerManagement" = {"MaxPowerState"=1,"CurrentPowerState"=1}
  "HIDServiceSupport" = Yes
  "IONameMatched" = "ACPI0008"
}


I know that there are tools that can use IOKit to access this value using C, ObjC, etc - but I explicitly would like to use a bash one-liner to try and grab the value.  

Has anyone been able to successfully do this via the command line and if so, how?
Read the current setting


  defaults read com.apple.BezelServices dAuto


Write 


  defaults write com.apple.BezelServices dAuto -boolean true/false