Passing variable value from CMD session to another

Discussion in 'Scripting' started by sacarias, Nov 8, 2019.

  1. sacarias

    sacarias MDL Junior Member

    Nov 21, 2018
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    I'm currently using this
    https://forums.mydigitallife.net/th...th-regular-user-and-admin.79962/#post-1536830
    on a script.

    This first does non-admin stuff, then elevates to admin, quits non-admin session, and opens a brand new CMD session as admin user to do the rest.

    So I'm running 2 different CMD sessions. I set a variable myvar=foo in the first unprivileged session. It's only valid for that session obviously. Is there a way to pass that variable value to the privileged CMD session once it starts?
     
  2. wilenty

    wilenty MDL Member

    Jan 15, 2014
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    #2 wilenty, Nov 8, 2019
    Last edited: Nov 8, 2019
    Simple as possible example:
    Code:
    @echo off
    
    rem your variable as example
    set myvar=foo
    
    rem Made by @UpGrade4
    title Check for permissions
    >nul 2>&1 "%SYSTEMROOT%\system32\cacls.exe" "%SYSTEMROOT%\system32\config\system"
    
    if '%errorlevel%' NEQ '0' (
        echo Requesting administrative privileges...
        goto UACPrompt
    ) else ( goto gotAdmin )
    
    :UACPrompt
        echo Set UAC = CreateObject^("Shell.Application"^) > "%temp%\getadmin.vbs"
        echo UAC.ShellExecute "%~s0", "%myvar%", "", "runas", 1 >> "%temp%\getadmin.vbs"
    
        cscript //B //Nologo "%temp%\getadmin.vbs"
        exit /B
    
    :gotAdmin
        if exist "%temp%\getadmin.vbs" ( del "%temp%\getadmin.vbs" )
        pushd "%CD%"
        CD /D "%~dp0"
    
    rem Do your stuff here as privileged user
    
    echo myvar=%1
    
    pause
    
    In the above example you get the "myvar" as "foo" as the first parameter in the second CMD -> "%1"="foo"
     
  3. sacarias

    sacarias MDL Junior Member

    Nov 21, 2018
    65
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    0
    Not working...

    At beginning of script I have something like
    if "%myvar%"==foo (goto admin) else (goto noadmin)

    After elevating and new clean CMD session as privileged user starts I still get
    "" = foo
    thus always going to NOADMIN
     
  4. wilenty

    wilenty MDL Member

    Jan 15, 2014
    195
    363
    10
    #4 wilenty, Nov 8, 2019
    Last edited: Nov 8, 2019
    Please get whole my scrip, from the example, and run it from explorer window, for me it's working - checked.
     
  5. sacarias

    sacarias MDL Junior Member

    Nov 21, 2018
    65
    1
    0
    Currently I have this:
    Code:
    @echo off
    
    if "%myvar%"==foo (goto ADMIN) else (goto NOADMIN)
    
    :NOADMIN
    REM Unprivileged stuff here
    [...]
    set myvar=foo
    
    (
       echo Set UAC = CreateObject^("Shell.Application"^) > "%TEMP%\elevate.vbs"
       echo UAC.ShellExecute "%~f0", "%myvar%", "", "runas", 1 >> "%TEMP%\elevate.vbs"
       cscript //B //Nologo "%TEMP%\elevate.vbs"
    
       exit /b
    )
    
    :ADMIN
    REM Admin stuff here
    (
       if exist "%TEMP%\elevate.vbs" del /f "%TEMP%\elevate.vbs" 2>&1
       pushd "%CD%"
       CD /D "%~dp0"
    )
    
    echo myvar=%1
    pause
    [...]

    I already know when elevating to privileged user it opens a totally new CMD session and starting the script *from very beginning*. Script clearly needs to do some stuff as unprivileged, and some other as privileged.
    When elevating to privileged user I need script to begin at :ADMIN label, not at the beginning. That's why I try checking the %myvar% variable at very first.

    But when just elevated and CMD starts in new session, I still get "if "" == foo". Thus :ADMIN label never actually enters.

    Some help please?
     
  6. rpo

    rpo MDL Expert

    Jan 3, 2010
    1,138
    947
    60
    Why don't you an argument? Following are some instructions i developped for the Sledgehammer script :
    Code:
    set "params=Problem_with_elevating_UAC_for_Administrator_Privileges"&if exist "%temp%\getadmin.vbs" del "%temp%\getadmin.vbs"
    fsutil dirty query %systemdrive%  >nul 2>&1 && goto :GotPrivileges
    ::    The following test is to avoid infinite looping if elevating UAC for Administrator Privileges failed
    If "%1"=="%params%" (echo Elevating UAC for Administrator Privileges failed&echo Right click on the script and select 'Run as administrator'&echo Press any key to exit...&pause>nul 2>&1&exit)
    cmd /u /c echo Set UAC = CreateObject^("Shell.Application"^) : UAC.ShellExecute "%~0", "%params%", "", "runas", 1 > "%temp%\getadmin.vbs"&cscript //nologo "%temp%\getadmin.vbs" && exit /b || (echo Elevating UAC for Administrator Privileges failed&echo Right click on the script and select 'Run as administrator'&echo Press any key to exit...&pause>nul 2>&1&exit)
    :GotPrivileges
    ...UAC.ShellExecute "%~0", "%params%", "", "runas", 1...
    and you test the presence of this param with If "%1"=="%params%"
     
  7. wilenty

    wilenty MDL Member

    Jan 15, 2014
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    10
    #7 wilenty, Nov 9, 2019
    Last edited: Nov 9, 2019
    @rpo I agree, he get only a part of my script, without checking my script and analyze it. Then, it does not work for him - it don't works like that. ;)

    For first the explanation.
    In the first check in your scrip the -> 'if "%myvar%"==foo (goto ADMIN) else (goto NOADMIN)' <- never return 'true', because -> "%myvar%" <- is not this same as -> foo <-, you missed double-quotes.
    For second, the variable "%myvar%" exists only in the :NOADMIN check function, but does not exists Globally in the the script. So, how it should work in your opinion?

    I already wrote to you that the variable %myvar% you get as the first parameter in the "brand new CMD" as %1 parameter.

    For first please check my script "as it's written", then analyze it and adapt the example to your script.
    Here is corrected example of your script:
    Code:
    @echo off
    
    if "%1"=="foo" (goto ADMIN) else (goto NOADMIN)
    
    :NOADMIN
    REM Unprivileged stuff here
    rem [...]
    set myvar=foo
    
    (
       echo Set UAC = CreateObject^("Shell.Application"^) > "%TEMP%\elevate.vbs"
       echo UAC.ShellExecute "%~f0", "%myvar%", "", "runas", 1 >> "%TEMP%\elevate.vbs"
       cscript //B //Nologo "%TEMP%\elevate.vbs"
    
       exit /b
    )
    
    :ADMIN
    REM Admin stuff here
    (
       if exist "%TEMP%\elevate.vbs" del /f "%TEMP%\elevate.vbs" 2>&1
       pushd "%CD%"
       CD /D "%~dp0"
    )
    
    echo myvar=%myvar%
    echo %%1=%1
    pause
    rem [...]
    
     
  8. sacarias

    sacarias MDL Junior Member

    Nov 21, 2018
    65
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    Yes, you were always right, I just could not understand it sooner. Apologies.
    I had indeed read your comment, but failed to understand that the variable was in the first parameter "%1", and not as the original name.
    Again, sorry for that.

    Just for notes, one last question.
    In this particular example I needed to pass a variable, %myvar%, as parameter for the second CMD. But in general, if no parameters needed to be passed, do I still need to pass the VBS script itself as parameter, "%TEMP%\elevate.vbs", or I could just leave that field empty?
     
  9. wilenty

    wilenty MDL Member

    Jan 15, 2014
    195
    363
    10
    OK.

    I don't know if I understand your question correctly.

    The "%TEMP%\elevate.vbs" run this script in elevated rights, for example with higher PowerUser/Admin rights. So, if you don't need to run this, or any, script as elevated, then you don't need to call this function. You can also transfer the "%1" parameter to the third script and/or the first script, for example: "Third_script.cmd %1", and in this script you can check for the "%1" parameter, if you want to know if the script was already elevated.