http://www.perlmonks.org?node_id=997436

anshumangoyal has asked for the wisdom of the Perl Monks concerning the following question:

I am using windows batch to check if Perl is installed on my machine and if it is not installed i install it using command line. This is my code: 
FOR /F "tokens=*" %%A IN ('perl -v ^| FIND "This is perl 5, version 12
+, subversion 4 (v5.12.4) built for MSWin32-x86-multi-thread"') DO SET
+ Variable=%%A
IF "%Variable%"=="This is perl 5, version 12, subversion 4 (v5.12.4) b
+uilt for MSWin32-x86-multi-thread" (
    ECHO Perl 5.12.4
    ECHO.
) ELSE (
    call msiexec /i win_packages\01_ActivePerl-5.12.4.1205-MSWin32-x86
+-294981.msi /q /l*v logs.txt >> Logs 2>&1
    IF %errorlevel% GTR 0 (
        echo 01 - Failed to Install 'ActivePerl-5.12.4.1205-MSWin32-x8
+6-294981.msi'. Got Error %errorlevel%.
        GOTO END
    )
)

[download]
Now the problem is if perl is not installed perl -v throws error which is displayed on output screen which I dont want. Can some one help me routing the output to > nul here.

Replies are listed 'Best First'.
Re: Dont Display STDER on Console
by BrowserUk (Patriarch) on Oct 05, 2012 at 10:59 UTC

    The perl link is tenuous at best, but ...

    C:\test>prel -v 2>nul | find "perl"

C:\test>perl -v 2>nul | find "perl"
This is perl, v5.10.1 built for MSWin32-x64-multi-thread
(with 2 registered patches, see perl -V for more detail)
this system using "man perl" or "perldoc perl".  If you have access to
+ the
Internet, point your browser at http://www.perl.org/, the Perl Home Pa
+ge.

    [download]
    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.

    RIP Neil Armstrong
[reply]
[d/l]
      It gives me this error: 2> was unexpected at this time. This was my code: 
      FOR /F "tokens=*" %%A IN ('perl -v 2>nul ^| FIND "This is perl 5, vers
+ion 12, subversion 4 (v5.12.4) built for MSWin32-x86-multi-thread"') 
+DO SET Variable=%%A

      [download]
[reply]
[d/l]
        It gives me this error: 2> was unexpected at this time.

        Escape the '>' in the same way that you escaped the '|'. 

        C:\test>for /f "tokens=*" %a in ('prel -v 2^>nul ^| find "perl"') do @
+echo %a

C:\test>for /f "tokens=*" %a in ('perl -v 2^>nul ^| find "perl"') do @
+echo %a
This is perl, v5.10.1 built for MSWin32-x64-multi-thread
(with 2 registered patches, see perl -V for more detail)
this system using "man perl" or "perldoc perl".  If you have access to
+ the
Internet, point your browser at http://www.perl.org/, the Perl Home Pa
+ge.

        [download]
        With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority".
        In the absence of evidence, opinion is indistinguishable from prejudice.

        RIP Neil Armstrong
[reply]
[d/l]

Back to Seekers of Perl Wisdom