restore the previous echo status - batch-file

Question

In a DOS Batch File subroutine, how can I turn off echo within the subroutine, but before returning, put it back to what it was before (either on or off)?
For example, if there was a command called echo restore, I would use it like this:
echo on
... do stuff with echoing ...
call :mySub
... continue to do stuff with echoing ...
exit /b
:mySub
#echo off
... do stuff with no echoing ...
echo restore
goto :EOF

Answer 1

My first attempt was an utter failure - thanks jeb for pointing out the errors. For those that are interested, the original answer is available in the edit history.
Aacini has a good solution if you don't mind putting your subroutine in a separate file.
Here is a solution that works without the need of a 2nd batch file. And it actually works this time! :)
(Edit 2 - optimized code as per jeb's suggestion in comment)
:mysub
::Silently get the echo state and turn echo off
#(
setlocal
call :getEchoState echoState
echo off
)
::Do whatever
set return=returnValue
::Restore the echo state, pass the return value across endlocal, and return
(
endlocal
echo %echoState%
set return=%return%
exit /b
)
:getEchoState echoStateVar
#setlocal
#set file=%time%
#set file="%temp%\getEchoState%file::=_%_%random%.tmp"
#(
for %%A in (dummy) do rem
) >%file%
#for %%A in (%file%) do #(
endlocal
if %%~zA equ 0 (set %~1=OFF) else set %~1=ON
del %file%
exit /b
)
If you are willing to put up with the slight risk of two processes simultaneously trying to access the same file, the :getEchoState routine can be simplified without the need of SETLOCAL or a temp variable.
:getEchoState echoStateVar
#(
for %%A in (dummy) do rem
) >"%temp%\getEchoState.tmp"
#for %%A in ("%temp%\getEchoState.tmp") do #(
if %%~zA equ 0 (set %~1=OFF) else set %~1=ON
del "%temp%\getEchoState.tmp"
exit /b
)

Answer 2

The simplest way is to not turn echo off in the first place.
Instead, do what you currently do with the echo off line to the rest of your subroutine - prefix all commands in the subroutine with an # sign. This has the effect of turning off echo for that command, but keeps the echo state for future commands.
If you use commands that execute other commands, like IF or DO, you will also need to prefix the "subcommand" with an # to keep them from being printed when echo is otherwise on.

Answer 3

The easiest way is to extract the subroutine to another .bat file and call it via CMD /C instead of CALL this way:
echo on
... do stuff with echoing ...
cmd /C mySub
... continue to do stuff with echoing ...
exit /b
mySub.bat:
#echo off
... do stuff with no echoing ...
exit /b
This way the echo status will be automatically restored to the value it had when the CMD /C was executed; the only drawback of this method is a slightly slower execution...

Answer 4

Here is a straight forward solution that relies on a single temporary file (using %random% to avoid race conditions). It works and is at least localization resistant, i.e., it works for the two known cases stated by #JoelFan and #jeb.
#set __ME_tempfile=%temp%\%~nx0.echo-state.%random%.%random%.txt
#set __ME_echo=OFF
#echo > "%__ME_tempfile%"
#type "%__ME_tempfile%" | #"%SystemRoot%\System32\findstr" /i /r " [(]*on[)]*\.$" > nul
#if "%ERRORLEVEL%"=="0" (set __ME_echo=ON)
#erase "%__ME_tempfile%" > nul
#::echo __ME_echo=%__ME_echo%
#echo off
...
endlocal & echo %__ME_echo%
#goto :EOF
Add this preliminary code to increase the solution's robustness (although the odd's are high that it's not necessary):
#:: define TEMP path
#if NOT DEFINED temp ( #set "temp=%tmp%" )
#if NOT EXIST "%temp%" ( #set "temp=%tmp%" )
#if NOT EXIST "%temp%" ( #set "temp=%LocalAppData%\Temp" )
#if NOT EXIST "%temp%" ( #exit /b -1 )
:__ME_find_tempfile
#set __ME_tempfile=%temp%\%~nx0.echo-state.%random%.%random%.txt
#if EXIST "%__ME_tempfile%" ( goto :__ME_find_tempfile )

Answer 5

I wasn't really happy with the solution above specially because of the language issue and I found a very simple one just by comparing the result from current echo setting with the result when explicitly set OFF. This is how it works:
:: SaveEchoSetting
:: :::::::::::::::::::::::::::
:: Store current result
#echo> %temp%\SEScur.tmp
:: Store result when explicitly set OFF
#echo off
#echo> %temp%\SESoff.tmp
:: If results do not match, it must have been ON ... else it was already OFF
#for /f "tokens=*" %%r in (%temp%\SEScur.tmp) do (
#find "%%r" %temp%\SESoff.tmp > nul
#if errorlevel 1 (
#echo #echo on > %temp%\SESfix.bat
) else (
#echo #echo off > %temp%\SESfix.bat
)
)
::
:: Other code comes here
:: Do whatever you want with echo setting ...
::
:: Restore echo setting
#call %temp%\SESfix.bat

Answer 6

I was looking for the same solution to the same problem, and after reading your comments I had an idea (which is not the answer to the question, but for my problem is even better).
I wasn't satisfied with the cmd.exe /c mysub.cmd because it makes hard or even impossible to return variables (I didn't check) - (couldn't comment because it's the first time I post here :)
Instead noticed that all we want -in the end- is to suppress stdout:
echo on
rem call "mysub.cmd" >nul
call :mysub >nul
echo %mysub_return_value%
GOTO :eof
:mysub
setlocal
set mysub_return_value="ApplePie"
endlocal & set mysub_return_value=%mysub_return_value%
GOTO :eof
It works fine with labelled subroutines, with subroutines contained in .cmd files, and I suppose it would work fine even with the cmd.exe /c variant (or start).
It also has the plus that we can keep or discard the stderr, replacing >nul with >nul 2>&1
I note that ss64.com scares kids like me stating that with call "Redirection with & | <> also does not work as expected".
This simple test works as expected. He must have been thinking of more complex situations.