WindowsBatch与LinuxShell比较[变量值来自文件或命令]

WindowsBatch与LinuxShell比较[变量值来自文件或命令]

 

 

一 Windows Batch

1) 如果变量的值来自文件,则必须类似set /p num=<num.txt 。
2)如果变量的值想来自命令的结果,则一些命令可以使用%%,例如set bbb=%time%,set aaa=%date%。对于一般的命令只能先输出到临时文件,然后再读入,例如time /t > ddd.txt set /p ddd=<ddd.txt。
3) 在for中可以使用命令,例如·time /t·。

实例:

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<!--<br /><br />Code highlighting produced by Actipro CodeHighlighter (freeware)<br />http://www.CodeHighlighter.com/<br /><br />--> @echo off

echo get the value from one txt file
rem the num.txt file only contains one line "001".

echo work well
set / p num =< num . txt
echo %num%

echo doesn't work
set num =< num . txt
echo %num%
type num . txt | set num =
echo %num%
type num . txt | set / p num =
echo %num%
set num =( ` print num . txt` )
echo %num%

echo get value from command
echo some command work well , such as % time % , % date %
set bbb = % time %
echo %bbb%
set aaa = % date %
echo %aaa%

echo general command doesn't work
set ccc =( ' time / t' )
echo %ccc%

echo one solution is to output the result to txt and then input it
time / t > ddd . txt
set / p ddd =< ddd . txt
echo %ddd%

echo specially , in for clause , ( ' time / t' ) is as one command .
echo and if also use setlocal enabledelayedexpansion , the way also can implement get value from command .
setlocal enabledelayedexpansion
for / f %%i in ( ' time / t' ) do (
echo %%i
set ti = %%i
echo !ti!
)

pause
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二 Linux Shell

1)超级简单,只需要使用·command parameters·。

实例:

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<!--<br /><br />Code highlighting produced by Actipro CodeHighlighter (freeware)<br />http://www.CodeHighlighter.com/<br /><br />--> # ! / bin / sh

ddd
= `cat ./ ddd . txt`
echo $ ddd

d
= ` date `
echo $ d
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完!

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