How to Capture Command Output to Variable in Windows Batch Scripting


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When working with batch files in Windows, capturing command output is fundamental for scripting automation. The standard approach uses the FOR /F loop construct:


@echo off
FOR /F "delims=" %%i IN ('your_command_here') DO SET var=%%i
echo %var%



Here's how to store system date in a variable:


@echo off
FOR /F "delims=" %%d IN ('date /t') DO SET current_date=%%d
echo Today is %current_date%



For commands producing multiple lines, you can either capture just the first line or process the entire output:


@echo off
:: Capture first line only
FOR /F "delims=" %%i IN ('dir /b') DO (
    SET first_file=%%i
    goto :break
)
:break
echo First file: %first_file%

:: Process all lines
FOR /F "delims=" %%f IN ('dir /b') DO (
    echo Processing: %%f
)




Error Handling with Redirection


To capture both stdout and stderr:


@echo off
FOR /F "delims=" %%i IN ('your_command 2^>^&1') DO SET output=%%i


Storing Output with Special Characters


Use usebackq option for paths or special characters:


@echo off
FOR /F "usebackq delims=" %%i IN (dir "C:\Program Files\*" /b) DO (
    echo Found: %%i
)




Checking Service Status

@echo off
FOR /F "tokens=3 delims=: " %%s IN ('sc query Winmgmt ^| find "STATE"') DO (
    SET service_state=%%s
)
echo Windows Management service is %service_state%


Network Configuration

@echo off
FOR /F "tokens=2 delims=:" %%i IN ('ipconfig ^| find "IPv4"') DO (
    SET ip=%%i
)
SET ip=%ip:~1%
echo Your IP address is %ip%



For temporary storage without variables, consider redirecting to files:


@echo off
your_command > temp.txt
SET /P var=


The SET /P approach reads the first line of a file into a variable, which can be useful in some scenarios.

The most reliable method for capturing command output in batch files is using FOR /F loops:


@echo off
FOR /F "delims=" %%G IN ('dir /b') DO (
    set "filelist=%%G"
    echo Current file: !filelist!
)

When dealing with commands that produce multiple lines, you'll need to process them differently:


@echo off
setlocal enabledelayedexpansion
set counter=0
FOR /F "delims=" %%A IN ('ipconfig /all') DO (
    set /a counter+=1
    set "line_!counter!=%%A"
)
echo Stored %counter% lines from ipconfig

Always account for potential command failures:


@echo off
set "output="
FOR /F "delims=" %%I IN ('ping nonexistenthost 2^>^&1') DO set "output=%%I"
if "%output%"=="" (
    echo Command failed or produced no output
) else (
    echo Command succeeded: %output%
)

For complex outputs, temporary files might be more reliable:


@echo off
set "tempfile=%temp%\%~n0_output.tmp"
systeminfo > "%tempfile%"
set /p sysinfo=<"%tempfile%"
del "%tempfile%"
echo First line of systeminfo: %sysinfo%

Extracting specific information from command output:


@echo off
FOR /F "tokens=2 delims=:" %%G IN ('sc query Winmgmt ^| find "STATE"') DO (
    FOR /F "tokens=*" %%H IN ("%%G") DO set "service_state=%%H"
)
echo Windows Management Instrumentation state: %service_state%