> You do it by pressing the ctrl + c keys. This pauses
> HTTrack. You also get the options to quit,
> interrupt, run as background task, run as blind
> background task or to cancel the mirroring. 

And if you want to control a background job:

To pause, you can create a file named hts-stop.lock in the project directory
(at the same level of hts-log.txt). HTTrack will erase it, wait for pending
transfers to finish, create a new file named hts-paused.lock, and will wait
until this file is erased. The mirror will continue from this point.