Retrieve matching strings from two text files - powershell

Question

I have a text file file_paths.txt that contains full paths on each line:
C:\MyFolder1\app1.exe
C:\MyFolder2\l1.dll
C:\MyFolder3\app2.exe
C:\MyFolder1\l2.dll
C:\MyFolder5\app3.exe
C:\MyFolder3\app4.exe
C:\MyFolder6\app5.exe
I also have file folders.txt that contains list of folders:
C:\MyFolder1
C:\MyFolder2
C:\MyFolder3
C:\MyFolder4
C:\MyFolder8
I need to iterate through the list of folders in folders.txt, match it with files in file_paths.txt and write the results to a file result.txt like this:
In C:\MyFolder1 more than one files has been found:
C:\MyFolder1\app1.exe
C:\MyFolder1\l2.dll
In C:\MyFolder2 one file has been:
C:\MyFolder2\l1.dll
In C:\MyFolder3 more than one files has been found:
C:\MyFolder3\app2.exe
C:\MyFolder3\app4.exe
In C:\MyFolder4 no files has been found.
In C:\MyFolder8 no files has been found.
My attempt that doesn't work:
$paths = [System.IO.File]::OpenText("file_paths.txt")
$folders = [System.IO.File]::OpenText("folders.txt")
$result = "result.txt"
try {
for(;;) {
$folder = $folders.ReadLine()
if ($folder -eq $null) { break }
"In ">> $folder >> ": `n" >> $result
for(;;) {
$path = $paths.ReadLine()
if ($path -eq $null) { break }
if ($path -contains $folder) {" ">>$path>>"`n">>$result }
}
}
} finally {
$paths.Close()
$folders.Close()
}

Answer 1

I would separate processing from reporting. First build a hashtable from the contents of folders.txt and add the lines from file_paths.txt to the matching keys:
$folders = #{}
Get-Content 'folders.txt' | ForEach-Object { $folders[$_] = #() }
Get-Content 'file_paths.txt' | ForEach-Object {
$line = $_
$($folders.Keys) | Where-Object {
$line -like "$_*"
} | ForEach-Object {
$folders[$_] += $line
}
}
Then you can output the resulting data structure like this:
$folders.Keys | ForEach-Object {
'In {0} {1} files have been found' -f $_, $folders[$_].Count
if ($folders[$_].Count -gt 0) {
$folders[$_] | ForEach-Object { "`t$_" }
}
} | Out-File 'result.txt'

Answer 2

Below is a script you can use to do exactly what you need.
Note the $folderPath and $filePath variables. Replace with absolute or relative (to where you execute the script) path of the file_paths.txt and folders.txt files.
$folderPath = 'folders.txt'
$filePath = 'file_paths.txt'
(Get-Content $folderPath).Split('`r`n') | ForEach-Object {
$folder = $_
$count = 0
$fileArray = #()
(Get-Content $filePath).Split('`r`n') | ForEach-Object {
$file = $_
if( $file | Select-String $folder -Quiet ) {
$count++
$fileArray += $file
}
}
if($count -ne 0) {
Write-Output "In $folder, $count files has been found."
$fileArray | ForEach-Object {
Write-Output "`t$_"
}
} else {
Write-Output "In $folder, no files has been found."
}
}