powershell-替换正则表达式

Question

I have the following script which I try to run on various html files

$files = $args[0];
$string1 = $args[1];
$string2 = $args[2];
Write-Host "Replace $string1 with $string2 in $files";
gci -r -include "$files" | 
 foreach-object { $a = $_.fullname; ( get-content $a ) | 
    foreach-object { 
            $_ -replace "%string1" , "$string2" | 
            set-content $a
    }
}

in an attempt to edit this line found in all the files.

<tr><td><a href="sampleTest.html">TestCase</a></td></tr>

I call the script from powershell like this (it's called replace.ps1)

./replace *.html sampleTest myNewTest

but instead of changing sampleTest.html to myNewTest.html it deletes everything in the doc except for the last line, leaving all of the files like so:

/html

in fact, no matter what arguments I pass in this seems to happen. Can anyone explain this/help me understand why it's happening?

Answer 1

Your loop structure is to blame here. You need to have the Set-Content located outside the loop. Your code is overwriting the file at every pass.

....
 foreach-object { $a = $_.fullname; ( get-content $a ) | 
    foreach-object { 
            $_ -replace "$string1" , "$string2" |         
    } | set-content $a
}

It also might have been a typo but you had "%string1" before which, while syntactically correct, what not what you intended.

Could also have used Add-Content but that would mean you have to erase the file first. set-content $a used at the end of the pipe is more intuitive.

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Your example is not one that uses regex. You could have used $_.replace($string1,$string2) with the same results.