Powershell 脚本自动化 gci

Question

I'm tying to automate gci in order to work on each row in a config file, where for each row I have as first column the path, and following it a list of files. Something like this:

C:\Users\*\AppData\Roaming\* *.dll
C:\Test file.txt,file2.txt

This means that gci will search for: *.dll in C:\Users*\AppData\Roaming* file.txt in C:\Test file2.txt in C:\Test

In order to do this I'm creating dynamically the where condition in the script below. Here the ps script I'm using

foreach($line in Get-Content .\List.txt) {
       
    try {
        $path,$files = $line.split(' ')
        $files = $files.split(',')
    }
    catch {
        $path = $line
        $files = "*.*"
    }
        
    if([string]::IsNullOrEmpty($files)){
        $files = "*.*"
    }
    
    $filter = $files -join(" -or `$_.Name` -like ")
    $filter = "`$_.Name` -like " + $filter
                
    echo "Searching Path: $path, Pattern: $filter" | out-file -append -encoding ASCII -filepath .\result.txt
        
    if ($path.Contains("*"))
    {
        gci -Path $path -Recurse | Where {$filter} | Select -ExpandProperty FullName | Out-String -Width 2048 | out-file -append -encoding UTF8 -filepath .\result.txt
    }
    else
    {
        gci -Path $path | Where {$filter} | Select -ExpandProperty FullName | Out-String -Width 2048 | out-file -append -encoding UTF8 -filepath .\result.txt
    }
}

The problem is that the where filter is not considered. All files are returned

First attempt , suggested by

foreach($line in Get-Content .\List.txt) {
    try {
        $path,$files = $line.split(' ')
        $files = $files.split(',')
    }
    catch {
        $path = $line
        $files = "*.*"
    }
        
    if([string]::IsNullOrEmpty($files)){
        $files = "*.*"
    }

    $filter = $files -join(" -or `$_.Name -like ")
    $filter = "`$_.Name -like " + $filter 

    $gciParams = @{
        Path = $Path
        Recurse = $Path.Contains('*')
    }

    "Searching Path: $path, Pattern(s): [$($files -join ',')]" | Add-Content -Path .\result.txt -Encoding ASCII
        
    Get-ChildItem @gciParams | Where $filter | Select -ExpandProperty FullName | Add-Content -Path .\result.txt -Encoding UTF8
}

Answer 1

If you want to create a piece of code and defer execution of it until later , you need a Script Block .

A Script Block literal in PowerShell is just {} , so for constructing script block to filter based on a single comparison, you'd want to define $filter like this:

$filter = {$_.Name -like $filter}

At which point you can pass it directly as an argument to Where-Object :

Get-ChildItem $path |Where-Object $filter

... but since you want to test against multiple wildcard patterns, we'll need to write a slightly different filtering routine:

$filter = {
  # Store file name of file we're filtering
  $FileName = $_.Name

  # Test ALL the patterns in $files and see if at least 1 matches
  $files.Where({$FileName -like $_}, 'First').Count -eq 1
}

Since the $filter block now references $files to get the patterns, we can simplify your loop as:

foreach($line in Get-Content .\List.txt) {
    try {
        $path,$files = $line.split(' ')
        $files = $files.split(',')
    }
    catch {
        $path = $line
        $files = "*.*"
    }
        
    if([string]::IsNullOrEmpty($files)){
        $files = "*.*"
    }

    $gciParams = @{
        Path = $Path
        Recurse = $Path.Contains('*')
    }

    "Searching Path: $path, Pattern(s): [$($files -join ',')]" | Add-Content -Path .\result.txt -Encoding ASCII
        
    Get-ChildItem @gciParams | Where $filter | Select -ExpandProperty FullName | Add-Content -Path .\result.txt -Encoding UTF8
}

Note that we no longer need to re-define $filter everytime the loop runs - the condition is based on the value of $files at runtime, so you can define $filter once before entering the loop and then reuse $filter every time.

The "trick" with using @gciParams (which allows us to remove the big if/else block) is known as splatting , but you could achieve the same result with Get-ChildItem -Path:$Path -Recurse:$Path.Contains('*') :)