Cannot execute some DOS commands in DosBox

Question

I'm trying to program batch script in dosbox, but there is no some commands.

For example, if I execute this code:

set var=helloworld
echo %var:~1,5%

I'll get empty line.

Also I can't execute FOR command. It says: 'Illegal command FOR'

Answer 1

command.com-like command processor included with DosBox is not fully compatible with command syntax of MS-DOS command.com or especially windows NT's cmd.exe command processors.

See this page for commands available to DosBox and their syntax. They may be similar but not the same to MS-DOS ones.

Your options are:

• use a batch file that runs outside dosbox for anything that does not need to be inside it

• copy and run command.com from a real MS-DOS or other DOS. You can get one from an image of a DOS boot floppy (or Windows 95, 98 or ME) which should be plentiful in the internet. Then refer to command-line manual for that DOS version. You will lose access to DosBox-specific commands inside it and it may try to needlessly hog the CPU as almost any other DOS program.

• write a program in any programming language that can be executed in DOS like C (free C compilers for DOS) and call it from DosBox. Some of the compilers are made free and available for download.