CODEWITHSUNDEEP
batch-filecmdstderr
Lahzey
Lahzey

Reputation: 393

How to read error output stream in batch file?

I have a batch script that starts a server. This server then prints out its logs to the STDOUT and STDERR in case of errors.

I want to redirect both STDOUT and STDERR to a tee command to split the output. Using the tee command from UnxUtils this worked just fine.

However in order to make my application portable I cannot depend on UnxUtils so I need to write my own tee command.

I wrote a batch script that reads out the STDOUT like suggested in this answer (2. codeblock).

This works, but only for the redirected STDOUT and not for the STDERR.

Note: Output from STDERR is missing in both the file and the command line.

How can I make it read both streams?

How I redirect the output (%1 is the server, %2 is the file I want the logs to go to)?

%1 2>&1 | %~dp0tee.bat -a %2

This works fine (as it calls UnxUtils, not my batch script):

%1 2>&1 | tee -a %2

How I read the input in tee.bat:

for /F "tokens=*" %%a in ('findstr /n $') do (
    set "line=%%a"
    setlocal EnableDelayedExpansion
    set "line=!line:*:=!"

    echo(!line!

    if %append%==true (
        echo(!line! >> %output%
    ) else (
        echo(!line! > %output%
    )
    endlocal
)

Upvotes: 0

Views: 1453

Answers (1)

lit
lit

Reputation: 16236

PowerShell has a Tee-Object cmdlet. The $Input variable receives stdin.

echo asf 2>&1 | powershell -NoLogo -NoProfile -Command "$Input | Tee-Object -FilePath './tee.txt'"

See also: https://stackoverflow.com/a/38668360/447901

Upvotes: 1

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