In addition to the perfect answer by Richard:
The batch functionality has been considerably improved since DOS time, but for many people this fact remained unnoticeable. Even though batch language is too rudimentary and inadequate to many more or less complicated tasks, many innovations makes it acceptable for a solving of a pretty wide range of simple ad-hoc problem. Even subprograms with parameters and their calls with proper returns to the caller (not jumps) are now available. Here is one interesting batch file which helps to generate documentation on current-day help. You can use it for all your batch needs:
@ECHO OFF
IF "%OS%"=="Windows_NT" SETLOCAL DISABLEDELAYEDEXPANSION
:: Version number for this batch file
SET MyVer=1.40
:: Display "about"
ECHO.
ECHO AllHelp.bat, Version %MyVer% for Windows NT 4 / 2000 / XP
ECHO Generate an HTML help file for "all" available commands
ECHO.
ECHO Note:
ECHO This batch file uses the redirected output of the HELP command to generate the
ECHO HTML file. Because some commands use "special" characters like ^&, ^<, and ^> in
ECHO their help screen, not all output is displayed correctly in the browser.
ECHO Known issues: skipped ^<space^> "tag" in CMD's special character list and skipped
ECHO \^<xyz and xyz\^> word position references in FINDSTR's output.
ECHO.
ECHO Written by Rob van der Woude
ECHO http://www.robvanderwoude.com
ECHO.
ECHO Improved white space handling by Johan Parlevliet
ECHO Further improvements for NT 4 by Ulf Lindb„ck
ECHO.
ECHO.
ECHO.
IF NOT "%OS%"=="Windows_NT" SET MyVer=
IF NOT "%OS%"=="Windows_NT" GOTO End
:: Store current code page and then set code page for European languages
FOR /F "tokens=*" %%A IN ('CHCP') DO FOR %%B IN (%%A) DO SET CHCP=%%B
CHCP 1252 >NUL 2>&1
:: Start writing HTML file
ECHO Writing HTML header . . .
> allhelp.htm ECHO ^<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"^>
>>allhelp.htm ECHO ^<HTML^>
>>allhelp.htm ECHO ^<HEAD^>
:: Read Windows version using VER command
FOR /F "tokens=1 delims=[" %%A IN ('VER') DO SET Ver=%%A
FOR /F "tokens=1* delims= " %%A IN ('ECHO.%Ver%') DO SET Ver=%%B
:: Read latest Service Pack from registry
CALL :GetSP
>>allhelp.htm ECHO ^<TITLE^>Help for all %Ver%%SP% commands^</TITLE^>
>>allhelp.htm ECHO ^<META NAME="generator" CONTENT="AllHelp.bat, Version %MyVer%, by Rob van der Woude"^>
>>allhelp.htm ECHO ^</HEAD^>
>>allhelp.htm ECHO.
>>allhelp.htm ECHO ^<BODY^>
>>allhelp.htm ECHO.
>>allhelp.htm ECHO ^<A NAME="Top"^>^</A^>
>>allhelp.htm ECHO.
>>allhelp.htm ECHO ^<CENTER^>
>>allhelp.htm ECHO ^<H1^>%Ver%%SP% commands^</H1^>
FOR /F "tokens=* delims=" %%A IN ('VER') DO SET Ver=%%A
>>allhelp.htm ECHO ^<H3^>%Ver%^</H3^>
>>allhelp.htm ECHO ^</CENTER^>
>>allhelp.htm ECHO.
>>allhelp.htm ECHO ^<P^>^ ^</P^>
>>allhelp.htm ECHO.
ECHO Creating command index table . . .
SET FirstCell=1
>>allhelp.htm ECHO ^<TABLE BORDER="0"^>
:: Skip 1 or 2 lines of HELP command's header
FOR /F "tokens=1 delims=[]" %%A IN ('HELP ^| FIND /N "."') DO IF %%A LEQ 2 SET Skip=+%%A
:: MORE's /T switch translates tabs to a fixed number of spaces; tip by Johan Parlevliet
:: In NT 4, MORE's /E switch may be necessary; tip by Ulf Lindb„ck
:: %Skip% skips 1 or 2 lines of HELP command's header
FOR /F "tokens=* delims=" %%A IN ('HELP ^| MORE /E %Skip% /T8') DO CALL :DispLine "%%A"
>>allhelp.htm ECHO ^</TD^>^</TR^>
>>allhelp.htm ECHO ^</TABLE^>
>>allhelp.htm ECHO.
>>allhelp.htm ECHO ^<P^>^ ^</P^>
>>allhelp.htm ECHO.
ECHO Writing help for each command:
:: MORE's /T switch translates tabs to a fixed number of spaces; tip by Johan Parlevliet
:: In NT 4, MORE's /E switch may be necessary; tip by Ulf Lindb„ck
FOR /F "tokens=* delims=" %%A IN ('HELP ^| MORE /E %Skip% /T8') DO CALL :DispFull "%%A"
ECHO Closing HTML file
>>allhelp.htm ECHO.
>>allhelp.htm ECHO ^<DIV ALIGN="Center"^>
>>allhelp.htm ECHO ^<P^>This HTML file was generated by:^<BR^>
>>allhelp.htm ECHO ^<B^>AllHelp.bat^</B^>, Version %MyVer%
>>allhelp.htm ECHO for Windows NT^ 4^ /^ 2000^ /^ XP^<BR^>
>>allhelp.htm ECHO Written by Rob van der Woude^<BR^>
>>allhelp.htm ECHO ^<A HREF="http://www.robvanderwoude.com"^>http://www.robvanderwoude.com^</A^>^</P^>
>>allhelp.htm ECHO ^</DIV^>
>>allhelp.htm ECHO.
>>allhelp.htm ECHO ^</BODY^>
>>allhelp.htm ECHO ^</HTML^>
ECHO.
ECHO An HTML help file "allhelp.htm" has been created and stored in the current
ECHO directory.
ECHO.
ECHO Now starting display of "allhelp.htm" . . .
START "AllHelp" allhelp.htm
:: End of main batch program
CHCP %CHCP% >NUL 2>&1
ENDLOCAL
GOTO:EOF
:: Subroutines
:DispLine
SET Line=%1
SET Line=%Line:(=^(%
SET Line=%Line:)=^)%
SET Line=%Line:"=%
SET Command=%Line:~0,8%
SET Command=%Command: =%
IF DEFINED Command CALL :DispCmdLine %Command%
FOR /F "tokens=1* delims= " %%a IN ('ECHO.%*') DO SET Descr=%%b
SET Descr=%Descr:"=%
>>allhelp.htm ECHO.%Descr%
GOTO:EOF
:DispCmdLine
IF "%FirstCell%"=="0" IF DEFINED Command (>>allhelp.htm ECHO ^</TD^>^</TR^>)
SET Command=%1
IF DEFINED Command (>>allhelp.htm ECHO ^<TR^>^<TH ALIGN="left" VALIGN="top"^>^<A HREF="#%Command%"^>%Command%^</A^>^</TH^>^<TD^>^ ^ ^ ^</TD^>^<TD^>)
SET FirstCell=0
SET Command=
GOTO:EOF
:DispFull
SET Line=%1
SET Command=%Line:~1,8%
SET Command=%Command: =%
IF DEFINED Command CALL :WriteFull %Command%
SET Command=
GOTO:EOF
:GetSP
SET SP=
:: Export registry tree to temporary file
START /WAIT REGEDIT.EXE /E "%Temp%.\%~n0.dat" "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion"
IF NOT EXIST "%Temp%.\%~n0.dat" GOTO:EOF
:: Read value of "CSDVersion" from temporary file
FOR /F "tokens=2 delims==" %%A IN ('TYPE "%Temp%.\%~n0.dat" ^| FIND /I "CSDVersion"') DO SET SP=%%~A
:: Check if value is valid
ECHO.%SP% | FIND /I "Service Pack" >NUL
IF ERRORLEVEL 1 SET SP=
DEL "%Temp%.\%~n0.dat"
:: Use a shorter notation
IF DEFINED SP SET SP=%SP:Service Pack=SP%
GOTO:EOF
:WriteFull
ECHO. %1 . . .
>>allhelp.htm ECHO.
>>allhelp.htm ECHO ^<A NAME="%~1"^>^</A^>
>>allhelp.htm ECHO.
>>allhelp.htm ECHO ^<H2^>%1^</H2^>
>>allhelp.htm ECHO.
>>allhelp.htm ECHO ^<PRE^>
>>allhelp.htm HELP %1
>>allhelp.htm ECHO ^</PRE^>
>>allhelp.htm ECHO.
>>allhelp.htm ECHO ^<A HREF="#Top"^>Back to the top of this page^</A^>
>>allhelp.htm ECHO.
>>allhelp.htm ECHO ^<P^>^ ^</P^>
>>allhelp.htm ECHO.
GOTO:EOF
:End
I'm really sorry that I cannot remember the source of this script, but its author Rob van der Woude and contributor Johan Parlevliet are written in the code, great thanks to them for this useful utility.
—SA
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