DOS ain't dead

> Is there a command in MS-DOS 6.21 that I can use to temporarily "insert" or
> "add-on" a directory to the existing PATH statement?

I am not near a PC, so from memory:
set oldpath=%path%
path=%path%;c:\testdir1;c:\testdir2
[do testing]
path=%oldpath%
set oldpath=

First line will backup the path to a temporary environment variable (providing you have room in the environment, if not you can always expand it). Second line adds 2 new directories onto the end of the path. Do testing line speaks for itself, 3rd line restores original path and 4th line removes temporary oldpath variable. Depenfing on what your doing not all the lunes ate required and a quick trick is to start a new command.com session, change the path then just do an exit when done.

Most of my batch files were designed to not require external programs if I could help it hence until you mentioned append I'd completely forgotten about it. A simple way of checking if the environment is big enough to backup another copy of the path is to do an if check like this:
if NOT "%path%"=="%oldpath%" goto PATHERROR

Re your autoexec.bat question I used to make mine runable again by doing a simple check if it had already run, e.g
if NOT "%booted%"=="" GOTO rerun
:firstrun
set booted=1
rem do 1st boot stuff e.g load keybd tsr
goto end

:rerun
set path=c:\dos;c:\bcc
goto end

:end
> The reason I want to do this is to try out a program. So I don't want to
> update the path statement in my AUTOEXEC.BAT file until I decide whether or
> not I'll continue to use this new program.

> EDIT: Never mind! After first posting this I think I just remembered the
> name of that command: APPEND! But now, I don't know how to delete my
> post. Is there a way to do that?
> ----------------------------------------------------------------------------
>
> Today I'm trying to figure out a shortcut for adding a directory to an
> already lengthy PATH statement.

No, I don't think APPEND is what you want. Also keep in mind that a PATH can only be approx. 128 bytes long, at least in most common environments (like your MS-DOS 6.21).

From cmdline, you can change the PATH easily, as mentioned, but most shells, including MS-DOS 6.21's, don't always expand env. vars when setting other environment variables. So "path c:\temp;%PATH%" doesn't work in MS-DOS 6.x (but works in 7.x's COMMAND.COM, IIRC). The workaround is to use a .BAT, since it always works inside there.

In my case, since I sometimes muck with the PATH and want to revert to a known stable state, I keep a file called MYPATH.BAT which switches back to the standard setup. In fact, I even call it from within AUTOEXEC.BAT:

REM N.B. this way avoids hardcoding the filename twice

for %%a in (c:\utils\mypath.bat) do if exist %%a call %%a


And here's MYPATH.BAT:


@echo off
REM mypath.bat
path c:\;c:\fdos\bin;c:\hx\bin;c:\utils
if not "%1"=="" path %PATH%;%1