批量读取文件到变量不起作用

Question

I am trying to redirect command output to variable using file as intermediary. I am able to redirect command output to file and but unable to read content of file into variable.

Batch File Script

echo off

pushd C:\Software
set TEMP_DIR=C:\Users\prade\Softwares

for /D %%i in (*) do (
    pushd "%%i"
    echo %TIME% > %TEMP_DIR%\a.log
    type %TEMP_DIR%\a.log
    for /f "delims=" %%x in (%TEMP_DIR%\a.log) do set duration=%%x
    echo %%i  %duration%
    popd
)
popd
echo on

I gives me below output

C:\Users\prade>echo off
 7:36:47.86
AutoHotKey
 7:36:47.86
cygwin64
 7:36:47.86
ffmpeg-20150518-git-451be67-win64-static
 7:36:47.86
mtn-200808a-win32
 7:36:47.86
ProcessExplorer
 7:36:47.86
tools

As you see there is nothing after directory name but type giving me content of file.

If I echo %duration% after batch file terminate in same cmd window, it gives me last time back.

What I am doing wrong?

Answer 1

@echo off

pushd C:\Software
set "TEMP_DIR=C:\Users\prade\Softwares"

setlocal enableDelayedExpansion
for /D %%i in (*) do (
    pushd "%%i"
    echo %TIME% > "%TEMP_DIR%\a.log"
    type %TEMP_DIR%\a.log
    for /f "usebackq delims=" %%x in ("%TEMP_DIR%\a.log") do set "duration=%%x"
    echo %%i  !duration!
    popd
)
popd
echo on

Answer 2

Add SETLOCAL EnableDelayedExpansion just below ECHO OFF and access duration with !duration! instead of %duration%.