China DOS Union

I renamed 4DOS.COM to COMMAND.COM and placed it in "C:\" and "C:\WINDOWS", so that it can replace the original COMMAND.COM in normal mode. However, if you select "Command prompt only" or "Safe mode command prompt only" in the boot menu, it cannot start normally. You have to enter "c:\command.com" every time to enter DOS.
Please ask all the experts how to solve this?

4dos seems to have an installation program. After installation, it will automatically add 4dos.com to the path. I seem to have installed it before, but I don't remember. I haven't tried booting from "command prompt only" or "safe mode command prompt only" either. But maybe it can be used after normal installation. You can check the help information yourself. If your English is poor, 1. Load Chinese character systems like ccdos under DOS, then load dfkc2k (for dos) (Oriental Express for dos), and then you can translate the English on the screen. 2. Use the DOS redirection function to write the English information on the screen to a file, then go to Windows and use Kingsoft Ciba or Oriental Express to translate and then view. Of course, option 1 is recommended. It's simple and pure DOS, heh heh...
PS: If it's because there is no "command only" or "safe command only" in 4dos.com, then there's no way, but since these two are in the options, it should be supported. These are all my guesses. Don't blame me if I'm wrong, heh heh...

If you don't execute shell=4dos.com (renamed to command.com) in CONFIG.SYS, you can't directly start 4DOS. I don't know why. I wonder if Teacher Mo has any way?

Asked the wrong person, I've never used external command interpreters like 4DOS or NDOS.

Oh, it seems there's no way around it. When DOS starts up, IO.SYS checks whether SHELL is already set, then checks if COMMAND.COM is illegal. Otherwise, it executes COMMAND.COM. If it doesn't match the default COMMAND.COM, it won't execute and will ask you to enter a shell program for it to run.

I just changed the value of SHELL in the CONFIG.SYS file to 4DOS, and it works normally under MS-DOS 7.10!

If you don't execute CONFIG.SYS and AUTOEXEC.BAT, etc., it won't work (for example, when you select "Safe mode command prompt only" in the boot menu), the system automatically loads DOS 7.1's COMMAND.COM. If you rename 4DOS.COM to COMMAND.COM, an error message will appear during startup, and you need to enter COMMAND.COM (that is, the renamed 4DOS.COM) again to start 4DOS. There's no way to make 4DOS load directly without CONFIG.SYS and these files.

It is better to directly type 4DOS after the > prompt, which will make the compatibility better. I once encountered a problem where placing 4DOS in Config.sys caused an issue, while running it directly didn't cause the problem.