What are all the functions of fastboot on android 4.4.4? I have recently been able to access fastboot but I have almost no knowledge about the different options inside it. Could someone please explain in details all the functions of fastboot?



Extra info


I am on a moto g 2013 with android 4.4.4
I am not rooted and do not have anything such as Clockwork mod installed
Fastboot allows you to send commands to your phone while in the bootloader. The bootloader is the one place that ADB is not running. 

Disclaimer, not all of these may work with your device.

fastboot oem unlock


Unlock your bootloader. If your device supports this, you can unlock your bootloader here. Most phones require an exploit in order to gain root access, phones like Nexus devices allow you to unlock the bootloader and then it is very easy to root, or install custom ROMs.  note: this will wipe all data off the phone.
Non-Nexus devices may require a code to go along with this command. so it would be called like fastboot oem unlock [the_code]. See fastboot oem get_unlock_data for how to get the code that goes with this command.


fastboot oem get_unlock_data


Motorola guide to unlock your device
I think this is a Motorola command, which will allow you to perform before the oem unlock.
This command will give you a code and you go to the Motorola website and enter the data. They will then give you a 20 character code that you use with oem unlock


fastboot devices


gets the list of devices that are connected to the computer. This is like the ADB devices command, but works on devices that are at the bootloader. 
It is good to use this to ensure you can properly connect to the device.


fastboot flash


Flashes a custom image to specific partitions on the device.


fastboot flash recovery recovery.img
fastboot flash boot boot.img
fastboot flash cache cache.img
fastboot flash userdata userdata.img
fastboot flash system system.img



fastboot erase


Erase partitions on the device [source]


fastboot erase system
fastboot erase data
fastboot erase cache



fastboot reboot


Yep, it reboots the device.




Normal Powerup


Just reboots the phone normal 


Recovery


Reboots the phone to the recovery


Factory


Seems to just boot the device normally. Maybe 'Safe Mode'? [Source]


Switch console


??


Barcodes


Brings up device serial number, ID numbers, SIM numbers, etc. as barcodes.


BP Tools


Baseband Processing Tools? Used for troubleshooting baseband [Source]