Update and Explain commands conflict or clash

[abhisekp]

While someone is updating the wiki via the update command, the wiki help command i.e. explain command doesn't work due to the way of updating the wiki by removing the .md files first.

rm data/wiki/*
cp data/fcc.wiki/*md data/wiki

In between execution of the above two commands, any calls to the explain command fails without any command event queue to execute it after update.

cc: @dcsan