CMD中各种命令耗时清单

xp5.1版的单核，2.4G，256M 测试
方法：for /l %%a in (1 1 %1)do %2 结合timediff 函数计算。

命令                                             效率（次/秒）
-----------------------------------------------------------------
echo ...                                         364.3
echo... >1.txt"                              119.3 (只要...是一行,耗时与...长度有关，但差别不明显)
echo ...>nul"                                 8772.6
call echo ...>nul                             1204.7
if 1==2 do .....                              61349.7
@echo off                                     71428.6
set d=%x%                                  42553.2
set/a n+=1                                    27411.8
call 空+goto:eof                             917.4
goto循环                                      1219.5
shift                                             102040
echo %%a|find >nul                      8474.5
echo %%a|findstr >nul                  8474.5
for /f ('more') echo >nul                2806.7
for /f ('type') echo >nul                 3932.1
for /f ('findstr .*')  echo >nul         4007.6
for /f ('find /v ""') echo >nul          2966.5
for /f  ( 文件) echo >nul                9807.5
echo.>1.txt                                 181.7
echo off>1.txt                            1666.7
del 1.txt                                      1961.7
pushd %tmp%                            2762.4
cd %tmp%                                  2808.7
pushd                                         76923.1
for /r (.)是for /f (dir/ad/s)速度的2倍。
 
 

频繁生成临时文件时用echo off>tmp效率最高。
call echo ...会大大降低echo 的速度。
多用if判断语句，与goto:eof会提高效率。