FreeDOS batch programming quick reference

A few weeks ago, I posted a "quick reference" for our new users. This reference showed the most common FreeDOS commands, including a few important notes for new users.

If you're looking to take the next step in FreeDOS, here's a handy quick reference guide to batch programming.

DOS batch programs are simple scripts that "batches up" several commands into one file. Batch programs have some basic flow control that you can use to do loops and jump to different segments of the program. In batch programs, reference variable values by enclosing the variable name with %, such as %PATH%

What do you want to do?	How to do it in a batch program:
Execute another batch script from within a script	CALL SCRIPT.BAT
Run a command for each file in a list	FOR %%F IN (*.TXT) DO EDIT %%F or at the command line: C:\> FOR %F IN (*.TXT) DO EDIT %F The loop variable name can only be one character.
Print a message	ECHO Hello world
Jump to a label in a batch file	:LOOP GOTO LOOP
Test the value of a string	IF %VAR%==Y ECHO Yes
Test if a file exists	IF EXIST TEMP.DAT DEL TEMP.DAT
Test the return value of the previous command	IF ERRORLEVEL 0 ECHO Success
Test the opposite	IF NOT ERRORLEVEL 0 ECHO Fail
Set the shell's search path for programs	PATH C:\FDOS\BIN;C:\MY\BIN or to reference the existing path: PATH %PATH%;C:\MY\BIN Use ; to separate paths.
Set a variable	SET TEMPFILE=TEMP.DAT
Shift the command line options	SHIFT or SHIFT 1 or any n Reference command line options as %1, %2, and so on.
A comment	REM This is a comment