How to replace multiple strings in a file using PowerShell
I am writing a script for customising a configuration file. I want to replace multiple instances of strings within this file, and I tried using PowerShell to do the job.
It works fine for a single replace, but doing multiple replaces is very slow because each time it has to parse the whole file again, and this file is very large. The script looks like this:
$original_file = 'pathfilename.abc'
$destination_file = 'pathfilename.abc.new'
(Get-Content $original_file) | Foreach-Object {
$_ -replace 'something1', 'something1new'
} | Set-Content $destination_file
I want something like this, but I don't know how to write it:
$original_file = 'pathfilename.abc'
$destination_file = 'pathfilename.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
One option is to chain the -replace operations together. The ` at the end of each line escapes the newline, causing PowerShell to continue parsing the expression on the next line:
$original_file = 'pathfilename.abc'
$destination_file = 'pathfilename.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
Another option would be to assign an intermediate variable:
$x = $_ -replace 'something1', 'something1aa'
$x = $x -replace 'something2', 'something2bb'
...
$x
为了让George Howarth的帖子能够在多个替代品中正常工作，您需要删除中断，将输出分配给一个变量（$ line），然后输出变量：
$lookupTable = @{
'something1' = 'something1aa'
'something2' = 'something2bb'
'something3' = 'something3cc'
'something4' = 'something4dd'
'something5' = 'something5dsf'
'something6' = 'something6dfsfds'
}
$original_file = 'pathfilename.abc'
$destination_file = 'pathfilename.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
使用PowerShell的第3版，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