如何在PowerShell v2中匹配和替换Get-Content和Set-Content对象中的字符串？

Question

Fairly new to Powershell and have been working to replace outdated copyrights within an assembly file with updated copyrights. Using the function below however fills the entire Data with a repeat of my newCopyright text.

What am I doing wrong?

function UpdateCopyright{
param            
(            
    [Parameter(Mandatory=$True,Position=1)]
    [String] $copyrightFileWithPath = "_"
)
try
{
    if ($copyrightFileWithPath -ne "_"){
        $currentYear         = (date).Year
        $copyrightNewTxt     = "Copyright © Company $currentYear"
        $copyrightSearchTxt  = "assembly: AssemblyCopyright"       
        $newCopyright = "[assembly: AssemblyCopyright(""$copyrightNewTxt"")]"
        $Data = (Get-Content $copyrightFileWithPath)          
        $copyrightInData = ($Data -match $copyrightSearchTxt)         
        $Data = ($Data -replace $copyrightInData, $newCopyright)
        Set-Content $copyrightFileWithPath $Data
        return $true
    }
    else{
        Write-Host ("ERROR: Invalid parameter to modify copyright for file " + $copyrightFileWithPath)
        return $false
    }
}
catch
{
    $ErrorMessage = $_.Exception.Message
    Write-Host ("ERROR: Exception while modifying copyright for file " + $copyrightFileWithPath + $ErrorMessage)
    return $false
}
}

Sample Input file:

using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

[assembly: AssemblyProduct("Test App")]
[assembly: AssemblyCopyright("Copyright © Company 2014 - 2018")]
[assembly: AssemblyCulture("")]
[assembly: ComVisible(false)]
[assembly: AssemblyVersion("2.11.0.4")]
[assembly: AssemblyFileVersion("2.11.0.4")]

Sample Output file:

using System.Reflection;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

[assembly: AssemblyProduct("Test App")]
[assembly: AssemblyCopyright("Copyright © Company 2018")]
[assembly: AssemblyCulture("")]
[assembly: ComVisible(false)]
[assembly: AssemblyVersion("2.11.0.4")]
[assembly: AssemblyFileVersion("2.11.0.4")]

Answer 1

You perform a match with:

$copyrightInData = ($Data -match $copyrightSearchTxt)

That just returns an array with 1 item: the one line in the file that matches your pattern. Then you run:

$Data = ($Data -replace $copyrightInData, $newCopyright)

That looks at the whole file, looks for something that matches the pattern defined in $copywriteInData , and replaces it with the new copywrite text. Here's the thing, this is a Regular Expression (RegEx for short) match. So $copywriteInData is the string [assembly: AssemblyCopyright("Copyright © Company 2014 - 2018")] . In RegEx anything within square brackets means that it should match any character within, so when you do the -replace it looks at the first character and decides:

Does it match: A
Does it match: s
Does it match: s
Does it match: e
Does it match: m

It proceeds until it finds a character within the [ ] that it matches, or runs out of characters within the [ ] to match against. How to fix this is to properly escape your string for RegEx matching:

$Data = $Data -replace [regex]::Escape($copyrightInData), $newCopyright

A simpler way to do this would be to better define what you want to replace, then just read the file, perform the replace, and write the file.

    $currentYear         = (date).Year
    $copyrightSearchTxt  = '(?<=\[assembly: AssemblyCopyright\(").*?(?="\)])'
    (GC $copyrightFileWithPath) -replace $copyrightSearchTxt, $currentYear | Set-Content $copyrightFileWithPath