如何使用PowerShell替换文件中的多个字符串

Question

我正在编写一个用于自定义配置文件的脚本.我想在这个文件中替换多个字符串实例,我尝试使用PowerShell来完成这项工作.

它适用于单个替换,但执行多次替换非常慢,因为每次它必须再次解析整个文件,并且此文件非常大.该脚本如下所示:

$original_file = 'path\filename.abc'
$destination_file =  'path\filename.abc.new'
(Get-Content $original_file) | Foreach-Object {
    $_ -replace 'something1', 'something1new'
    } | Set-Content $destination_file

我想要这样的东西,但我不知道如何写它:

$original_file = 'path\filename.abc'
$destination_file =  'path\filename.abc.new'
(Get-Content $original_file) | Foreach-Object {
    $_ -replace 'something1', 'something1aa'
    $_ -replace 'something2', 'something2bb'
    $_ -replace 'something3', 'something3cc'
    $_ -replace 'something4', 'something4dd'
    $_ -replace 'something5', 'something5dsf'
    $_ -replace 'something6', 'something6dfsfds'
    } | Set-Content $destination_file

Answer 1

一种选择是将-replace操作链接在一起.在`每一行的末尾逸出换行符,引起PowerShell来继续解析下一行的表达:

$original_file = 'path\filename.abc'
$destination_file =  'path\filename.abc.new'
(Get-Content $original_file) | Foreach-Object {
    $_ -replace 'something1', 'something1aa' `
       -replace 'something2', 'something2bb' `
       -replace 'something3', 'something3cc' `
       -replace 'something4', 'something4dd' `
       -replace 'something5', 'something5dsf' `
       -replace 'something6', 'something6dfsfds'
    } | Set-Content $destination_file

另一种选择是分配一个中间变量:

$x = $_ -replace 'something1', 'something1aa'
$x = $x -replace 'something2', 'something2bb'
...
$x

Answer 2

要获得George Howarth使用多个替换项正常工作的帖子,您需要删除中断,将输出分配给变量($ line),然后输出变量:

$lookupTable = @{
    'something1' = 'something1aa'
    'something2' = 'something2bb'
    'something3' = 'something3cc'
    'something4' = 'something4dd'
    'something5' = 'something5dsf'
    'something6' = 'something6dfsfds'
}

$original_file = 'path\filename.abc'
$destination_file =  'path\filename.abc.new'

Get-Content -Path $original_file | ForEach-Object {
    $line = $_

    $lookupTable.GetEnumerator() | ForEach-Object {
        if ($line -match $_.Key)
        {
            $line = $line -replace $_.Key, $_.Value
        }
    }
   $line
} | Set-Content -Path $destination_file

Answer 3

使用PowerShell版本3,您可以将替换调用链接在一起:

 (Get-Content $sourceFile) | ForEach-Object {
    $_.replace('something1', 'something1').replace('somethingElse1', 'somethingElse2')
 } | Set-Content $destinationFile

Answer 4

假设每行只能有一个'something1'或'something2'等,您可以使用查找表:

$lookupTable = @{
    'something1' = 'something1aa'
    'something2' = 'something2bb'
    'something3' = 'something3cc'
    'something4' = 'something4dd'
    'something5' = 'something5dsf'
    'something6' = 'something6dfsfds'
}

$original_file = 'path\filename.abc'
$destination_file =  'path\filename.abc.new'

Get-Content -Path $original_file | ForEach-Object {
    $line = $_

    $lookupTable.GetEnumerator() | ForEach-Object {
        if ($line -match $_.Key)
        {
            $line -replace $_.Key, $_.Value
            break
        }
    }
} | Set-Content -Path $destination_file

如果你能拥有这些的不止一个,只是删除break的if声明.

Answer 5

第三种选择,对于流水线单行程,是嵌套-replaces:

PS> ("ABC" -replace "B","C") -replace "C","D"
ADD

和:

PS> ("ABC" -replace "C","D") -replace "B","C"
ACD

这样可以保留执行顺序,易于阅读,并且非常适合管道.我更喜欢使用括号进行显式控制,自我记录等.没有它们可以工作,但你相信这有多远？

-Replace是一个比较运算符,它接受一个对象并返回一个推测修改过的对象.这就是您可以如上所示堆叠或嵌套它们的原因.

请参阅:

help about_operators