You are getting two very different methods confused here.
1 - there is the method of using a TTL serial cable and connecting to a device. This is where you manually type in commands at the devices boot prompt in a console window. That is this thread.
2 - there is the other method which is where you do NOT need a serial cable and are replying on the commands.txt file. The "easy" method. That method relies on the fact that almost all Dahua devices at boot will for a moment initialize a network connections and looks for a file named upgrade_info_7db780a713a4.txt on a
TFTP server. That method is in another thread here
Dahua IPC EASY unbricking / recovery over TFTP
These are TWO DIFFERENT methods and used in totally different ways. The method in this thread does NOT use the "commands.txt, commands.bat, etc" files. Those are strictly related to the method in the other thread.
For the purpose of clarity. The commands used in that file from the other thread are indeed some of the very same commands used at a console prompt in this thread.
There are also some commands that while valid for one device are not valid on another. Different devices have different file structures and a few devices have some files that others do not.
In either method a "run" command has a specific purpose and is ONLY for a very specific file.
These are ones that I know of, and again, not EVERY device has every one of these. NOTE - these are the "run" commands I figured out from my A46 and some from my DVR and others reading on these forums. Not likely that any device will have all of these but I thought it could be useful to know about as many as possible.
da=dhboot.bin.img (can also optionally load dhboot-min.bin.img or u-boot.bin.img depending on device)
dr=romfs-x.squashfs.img
dk=kernel.img
du=user-x.squashfs.img
dw=web-x.squashfs.img
dc=custom-x.squashfs.img
dt=data-x.squashfs.img
dp=partition-x.cramfs.img
dl=logo-x.squashfs.img
ds=tftp slave-x.squashfs.img
dx=u-boot_slave.bin.img
pd=pd-x.squashfs.img
pm=575s_PMX.bin.img (this is on my DVR but I do not have that file)
tk=uImage (my A46 showed this is hawthorn.dts.dtb. I have no idea what this one is, my firmware does not have that file but the printenv on my serial console did show it as a valid "run" type command)
up=update.img (if the firmware you want to flash has an update.img, use this one ONLY and skip all the others)
NOTE: each of these "run" commands can ONLY be used with the exact file name shown.
There are a few different ways that Dahua provides firmware and each is in a different format for loading in a different manner. There are two that are an "all in one" type of firmware which contain all of the different files. One will be named update.img which is the only "all in one" type that can be used with either this serial console method or the "easy" method in the other thread. The other "all in one" type is what you have which will be a firmware named "General_Multi3_VTO2000A_EngItlFreGetDutSpaPor_P_16M_V3.200.0000.0.R.20170912.bin" or something like that. That type of a firmware file is intended for updating firmware within the devices interface or one of the software
tools and is not directly usable in this method or the "easy" method in the other thread. As it is that firmware file CANNOT be used with ANY of the "run" commands. Simply renaming that type of a firmware file will also NOT work. The third type of firmware that Dahua provides is broken into multiple individual parts and can ONLY be used via this serial console method or with the "easy" method in the other thread. Neither method is particularly "easy" for the average computer user though.
If the only type of firmware you can find for your device is the type intended for using in the devices web interface like "General_Multi3_VTO2000A_EngItlFreGetDutSpaPor_P_16M_V3.200.0000.0.R.20170912.bin" or something like that you can extract that to a folder. You would need 7zip or some other compressed file extractor. Extraction will also likely give you an error but still should extract the majority of the firmware files fine. Once extracted you should then have the individual .img files related to the commands listed above.