Merge pull request #4542 from ivanov/history-clear new `ipython history clear` subcommand This new subcommand is equivalent to ipython history trim --HistoryTrim.keep=0, which is now supported (and also has a more convenient --keep alias) This command comes with a fix to bash completion of flags for ipython history subcmd also included is a tiny fix for nbconvert completion that was pointed out by @jakobgager in #4528 also included is a change to our utils.io.ask_yes_no function that allows for specifying the behavior of a KeyboardInterrupt.