Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!hp-pcd!hplsla!davidr
From: davidr@hplsla.HP.COM (David M. Reed)
Newsgroups: comp.sys.ibm.pc
Subject: Re: DOS 3.30 PATH and Environment lengths
Message-ID: <5190026@hplsla.HP.COM>
Date: 27 Jul 89 21:17:17 GMT
References: <3695@i.sei.cmu.edu>
Organization: HP Lake Stevens, WA
Lines: 55

My experience is that while you can expand the size of the DOS environment,
none of the environment variables can take more than ~128 bytes.  When I 
found that I could not increase the length of my PATH variable I began to
use a variety of tricks.  One thing is to use short directory names (2-4
characters):

(okay)            PATH=C:\BAT;C:\UTIL;C:\DOS;C:\WIN

And while I like to have a fairly structured directory system, I try to make 
certain that and directory that needs to be in the search path is at the root
level, thus avoiding the lenthy /dir/subdir names:

(not okay)        PATH=C:\USR\BIN;C:\USR\LOCAL\BIN;C:\USR\CONTRIB\BIN
(okay)            PATH=C:\BIN;C:\LBIN;C:\CBIN

One trick I have not used but know of is to use the SUBST command preceeding
the PATH statement.  That way you can assign a psuedo-drive letter to a
path which makes for much shorter entries:

(in CONFIG.SYS)   LASTDRIVE = Z

(in AUTOEXEC.BAT) SUBST E: C:\USR\LOCAL\BIN
                  PATH=C:\;E:

The most recent thing I have been doing is to keep directories out of the
PATH variable that are not used frequently, or do not have a lot of programs
to be found in them.  (Generally I have a directory in the search PATH only
if it has a lot of programs.)  I start my major applications from BATch files
(all of which I place in the C:\BAT directory), that way their directory does
not need to be in the search PATH:

(C:\BAT\JUNK.BAT)   ECHO OFF
                    PUSHDIR > NUL
                    C:
                    CD \PROG_DIR
                    PROGRAM %1 %2 %3 %4 %5
                    POPDIR > NUL

NOTE: I like to see the initial ECHO OFF so that I can easily distinguish
whether I am starting a program directly or indirectly, the latter being 
something I am able to modify if I need or want.

Some applications need to have their directory in the search PATH, but since 
their directory only needs to be in the search PATH while the program is 
running, then modify the PATH before starting:

(C:\BAT\WORD.BAT)   ECHO OFF
                    PUSHDIR > NUL
                    SET OLDPATH=%PATH%
                    SET PATH=%PATH%;C:\PROG_DIR
                    C:
                    CD \PROG_DIR
                    PROGRAM %1 %2 %3 %4 %5
                    SET PATH=%OLDPATH%
                    POPDIR > NUL