Quick way to change device/emulator locale from shell

To change locale: adb shell setprop persist.sys.language en;setprop persist.sys.country US;stop;start

To import contacts: adb shell am start -a android.intent.action.VIEW -n com.android.contacts/.vcard.ImportVCardActivity -d file:/mnt/sdcard/VCF_FILE_NAME

To clear contacts: adb shell pm clear com.android.providers.contacts