How to Capture Command Output to Variable in Windows Batch Scripting



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%