The SETLOCAL command in a batch file, begins localization of the environment variables. SETLOCAL makes an image of the environment variables and ENDLOCAL restores that image.

You can have up to 32 levels of localization:

...
setlocal
set username=Jerry
call :levela
enlocal
goto end
:levela
setlocal
set username=jennifer
....
endlocal
:end

Using the SETLOCAL and ENDLOCAL commands in tip 964, JSILLD.bat can be reduced from 100 statements to 88 statements. Here is the part of the script that is changed:

Revised	Previous
@echo off	@echo off
setlocal
if "%1" "" goto syntax	if "%1""" goto syntax
if "%2" "" goto syntax	if "%2""" goto syntax
if "%3" "" goto begin	if "%3""" goto begin
if /i "%3" "/n" goto begin	if /i "%3""/n" goto begin
:syntax	:syntax
@echo Syntax: JSILLD File yyyymmdd \[/N\]	@echo Syntax: JSILLD File yyyymmdd \[/N\]
endlocal	set dte=
	set XX=
goto end	goto end
:begin	:begin
if /i "%2" "/n" goto syntax	if /i "%2""/n" goto syntax
set dte=%2	set dte=%2
set XX=%dte:~0,4%	set XX=%dte:~0,4%
if "%XX%" LSS "1993" goto syntax	if "%XX%" LSS "1993" goto syntax
set XX=%dte:~4,2%	set XX=%dte:~4,2%
if "%XX%" LSS "01" goto syntax	if "%XX%" LSS "01" goto syntax
if "%XX%" GTR "12" goto syntax	if "%XX%" GTR "12" goto syntax
set XX=%dte:~6,2%	set XX=%dte:~6,2%
if "%XX%" LSS "01" goto syntax	if "%XX%" LSS "01" goto syntax
if "%XX%" GTR "31" goto syntax	if "%XX%" GTR "31" goto syntax
set never=%3	set never=%3
set file=%1	set file=%1
if exist %file% del /q %file%	if exist %file% del /q %file%
for /f "Skip=4 Tokens=*" %%i in ('net users') do call :parse "%%i"	for /f "Skip=4 Tokens=*" %%i in ('net users') do call :parse "%%i"
endlocal	set str=
	set substr=
	set ustr=
	set txt=
	set fullname=
	set never=
	set file=
	set dte=
	set XX=
	set YY=
	set MM=
	set DD=
	set YMD=
goto end	goto end

You can use a little trick to have SETLOCAL and ENDLOCAL in a batch and still return environment variables. Assume a script contains:

@echo off
setlocal
...
set /a tmp1=1
set /a tmp2=2
set /a tmp3=3
...
set /a var1=%tmp1% + %tmp3%
...
set /a var2=%tmp2% * %var1%
...
endlocal
:end

Because the shell evaluates environments variables in a command before executing it, you could return var1 and var2 by changing the endlocal (above) to:

endlocal & set /a var1=%var1% & set /a var2=%var2%

The shell interprets this as:

endlocal & set /a var1=4 & set /a var2=8

before executiion.