Some commands can change many pages. The consequences of an error are under your responsibility! After an error, it is sometimes possible to correct mistakes using the bot, but not always!
Before using the replace and regexp commands to many pages, it is strongly advised to test them first on one page.
Once a request is launched, it can't be stopped. It is therefore useless to write on the template Request being processed (when the line is yellow), as this does not change the bot behaviour, except that it won't know where to write the results.
To use this bot, check the manual here: User:ThomasBot/Help:Bots.