How to make the terminal auto-complete from the command history

In step 2 you copied the original hosts file to a backup location at ~/Documents/hosts-backup (i.e. in your documents folder).

All you should need to do is rename that file to hosts and then copy it to /private/etc/hosts (overwriting the edited file) to undo any damage that you may have done.

However if you only got to Step 3 you may not even have edited the file yet - in which case a reboot should be sufficient.

oh boy, from kinesis [website][4]

Note: Modifier actions from one USB device cannot modify the input of a second USB device due to limitations designed into the Apple operating system. Example: Shift, Control, Command, or Option keystrokes programmed into the footswitch cannot modify the input of a separate USB keyboard or mouse. However, a key sequence like ‘Cmd-W’ or ‘Cmd-Shift-left arrow’ will work on a Macintosh if the entire sequence of keystrokes has been pre-programmed into the footswitch. (Footswitch can only be programmed on a Windows PC).

I just tried this using my usb keyboard and built in osx keyboard and it seems to be true. I can hit control + left on my usb keyboard and it works fine but control on my usb keyboard + left on the builtin keyboard does not work:(

Great news! Karbiner is a mature open source project that allows modifing across devices as a feature. https://pqrs.org/osx/karabiner/document.html.en

Share state of modifier keys with all connected keyboards: When you are using multiple keyboards, modifier keys are shared with all keyboards. For example, pressing "shift key on keyboard1" and "space key on keyboard2" sends shift-space.