When using an external (Windows) keyboard with your Mac you probably want to modify your keyboard layout, for instance change Windows button to Option and Alt button to Command.
A nice program for this is KeyRemap4MacBook, but that is not what this article is about, since there is a lot of information about that program already on the web.
My issue is that I switch a lot between the laptop keyboard and the external keyboard, depending on if I sit by my desk or not. There is a nice thing i KeyRemap4MacBook to switch profiles. However I do not want to manually switch profiles every time I (dis-)connect my external keyboard.
So I created a bash script that detects if an external keyboard is connected and then I schedule this with crontab.
The script:
#!/bin/bash
externalConnected=`/usr/sbin/system_profiler SPUSBDataType|grep -i keyboard|grep -vi internal`
if [[ "" == "$externalConnected" ]]; then
newSetting=1
else
newSetting=0
fi
currentSetting=`/usr/libexec/PlistBuddy -c "Print :selectedIndex" ~/Library/Preferences/org.pqrs.KeyRemap4MacBook.plist`
if [[ $newSetting != $currentSetting ]]; then
/usr/libexec/PlistBuddy -c "Set :selectedIndex $newSetting" ~/Library/Preferences/org.pqrs.KeyRemap4MacBook.plist
killall KeyRemap4MacBook
fi
This assumes that you have two profiles in KeyRemap4MacBook and that the first one is the profile for the external keyboard!
Crontab:
* * * * * ~/Scripts/detect_external_keyboard.sh
* * * * * sleep 15; ~/Scripts/detect_external_keyboard.sh
* * * * * sleep 30; ~/Scripts/detect_external_keyboard.sh
* * * * * sleep 45; ~/Scripts/detect_external_keyboard.sh
As you see I had to add 4 rows to make it run more often than once per minute.
