Loop through files in a directory using PowerShell

Give this a try:

Get-ChildItem "C:\Users\gerhardl\Documents\My Received Files" -Filter *.log | 
Foreach-Object {
    $content = Get-Content $_.FullName

    #filter and save content to the original file
    $content | Where-Object {$_ -match 'step[49]'} | Set-Content $_.FullName

    #filter and save content to a new file 
    $content | Where-Object {$_ -match 'step[49]'} | Set-Content ($_.BaseName + '_out.log')
}

If you need to loop inside a directory recursively for a particular kind of file, use the below command, which filters all the files of doc file type

$fileNames = Get-ChildItem -Path $scriptPath -Recurse -Include *.doc

If you need to do the filteration on multiple types, use the below command.

$fileNames = Get-ChildItem -Path $scriptPath -Recurse -Include *.doc,*.pdf

Now $fileNames variable act as an array from which you can loop and apply your business logic.

To get the content of a directory you can use

$files = Get-ChildItem "C:\Users\gerhardl\Documents\My Received Files\"

Then you can loop over this variable as well:

for ($i=0; $i -lt $files.Count; $i++) {
    $outfile = $files[$i].FullName + "out" 
    Get-Content $files[$i].FullName | Where-Object { ($_ -match 'step4' -or $_ -match 'step9') } | Set-Content $outfile
}

An even easier way to put this is the foreach loop (thanks to @Soapy and @MarkSchultheiss):

foreach ($f in $files){
    $outfile = $f.FullName + "out" 
    Get-Content $f.FullName | Where-Object { ($_ -match 'step4' -or $_ -match 'step9') } | Set-Content $outfile
}