Used in conjunction with an empty option:--pid option: untrack _all_
process IDs (clear the whitelist).
-option:-p, option:--pid[='PID'[,'PID']...]::
+option:-p ['PID'[,'PID']...], option:--pid[='PID'[,'PID']...]::
Untrack process IDs 'PID' (remove them from the current whitelist).
+
The 'PID' argument must be omitted when also using the option:--all