Reboot android into recovery/download mode using adb (without buttons)

Hi guys,

Sometimes it's useful to reboot your android phone into recovery/download mode. For example, if you want to do a factory reset or root your device. One of the ways of rebooting into such mode is by using special combination of buttons. But if you don't know such combination, there is another way of doing that - by using usb cable and special program called 'adb' (android debug bridge). Below we will discuss this second way. Also, I will be doing everything on Linux, because this is what my website about. But you can also do it on Windows or Mac OS.