Loop through files in a directory using PowerShell

Question

How can I change the following code to look at all the .log files in the directory and not just the one file?

I need to loop through all the files and delete all lines that do not contain "step4" or "step9". Currently this will create a new file, but I'm not sure how to use the for each loop here (newbie).

The actual files are named like this: 2013 09 03 00_01_29.log. I'd like the output files to either overwrite them, or to have the SAME name, appended with "out".

$In = "C:\Users\gerhardl\Documents\My Received Files\Test_In.log"
$Out = "C:\Users\gerhardl\Documents\My Received Files\Test_Out.log"
$Files = "C:\Users\gerhardl\Documents\My Received Files\"

Get-Content $In | Where-Object {$_ -match 'step4' -or $_ -match 'step9'} | `
Set-Content $Out

Vincent G · Accepted Answer · 2016-03-22 13:59:55Z

518

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')
}

edited Mar 22, 2016 at 13:59

Vincent G

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answered Sep 17, 2013 at 11:37

Shay Levy

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3 Comments

user2725402 Over a year ago

thanks. The BaseName part does not work (version 1) - but I managed by first creating a backup of the full file then making the change to the original file.

Shay Levy Over a year ago

For v1, you can use the following to extract the base name: [io.path]::GetFileNameWithoutExtension($name)

M-- Over a year ago

If I replace BaseName with FullName I get what I want.

PVitt · Accepted Answer · 2019-02-13 20:24:41Z

148

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
}

edited Feb 13, 2019 at 20:24

answered Sep 17, 2013 at 10:23

PVitt

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8 Comments

user2725402 Over a year ago

This creates one output file named "out.log". How can I create a separate output file for each input file?

PVitt Over a year ago

@user2725402 I added an input dependend output file that is named <input file name>out

user2725402 Over a year ago

okay 2 new issues... this now for some reason does the opposite of the match, i.e. it creates a file with only records NOT containing "step4" or "step9". Also, it is renaming using "out" as an extension, so files are named "XXX.log.out" - I tried using BaseName but can't get it right.

Soapy Over a year ago

You can also do foreach ($f in Get-ChildItem "C:\Users\gerhardl\Documents\My Received Files\") { ... }

Mark Schultheiss Over a year ago

or use ForEach ($f in $files){...}

|

Sarath Subramanian · Accepted Answer · 2016-04-28 15:23:59Z

47

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.

answered Apr 28, 2016 at 15:23

Sarath Subramanian

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2 Comments

til_b Over a year ago

What bugged me was the omission of hidden and/or system files. To also see them you have to use the -Force parameter to Get-ChildItem. See its doc at learn.microsoft.com/en-us/powershell/module/… .

Design.Garden Over a year ago

Note: The Include parameter only works when either the command includes the Recurse parameter or the path leads to the contents of a directory (stackoverflow.com/a/41700792)

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