Windows PowerShell中的管道

Question

I have two files:

File1:

dir1
dir2
dir3

File2:

f1
f2
f3

File1 contains a list of directories and File2 contains a list of files. I want to copy all files in File2 which are in my current directory into directories mentioned in File1 using PowerShell. For doing the same I am using the following command:

Get-Content File2  | ForEach-Object {
    $dir = $_ ;
    Get-Content File1 |
        Copy-Item ("c:\users\")+$_ (("c:\users\")+$dir+("/")+($_))) 

However, I am getting errors with this. Can someone please help me form the right query

The error which I am getting is:

The input object cannot be bound to any parameters for the command either because the command does not take pipeline input or the input and its properties do not match any of the parameters that take pipeline input.

I want f1, f2, f3 to be copied to dir1. Again f1, f2, f3 to be copied to dir2. And again f1, f2, f3 to be copied to dir3.

Answer 1

Copy-Item has only one parameter that accepts a source path as pipeline input: -Path (or -LiteralPath , depending on which parameter set is used). However, you're already passing a source path to -Path as the first positional parameter, so there's no parameter left that could accept the pipeline input. You cannot "overlay" positional parameters and pipeline input. It's either one or the other. Also, the $_ in the Copy-Item statement is not what you expect. It's actually the current object from the ForEach-Object , not the current object from the Get-Content output. You'd need to pipe Get-Content into another ForEach-Object and put Copy-Item into that loop for it to work the way you expect. And as Jeff Zeitlin pointed out in the comments, your directory names actually come from File1, so you need to read that file for the outer loop, and File2 (with the file names) for the inner loop.

Get-Content File1 | ForEach-Object {
    $dir = $_
    Get-Content File2 | ForEach-Object {
        Copy-Item "C:\users\${_}" "C:\users\${dir}\${_}"
    }
}

However, that's not required in your scenario, since you could simple prepend the output of Get-Content File1 with the path prefix and use that as input for Copy-Item :

Get-Content File1 | ForEach-Object {
    $dir = $_
    (Get-Content File2) -replace '^', 'C:\users\' |
        Copy-Item -Destination {'C:\users\{0}\{1}' -f $dir, (Split-Path -Leaf $_)}
}

Note that you need curly brackets around the argument of the parameter -Destination for this to work.

Side note: Avoid string concatenation wherever possible. PowerShell can expand variables inside double-quoted strings, which greatly improves readability.