PowerShell Weekly
PowerShell Weekly

PoshBytes: Your .NET Path Toolkit for PowerShell

Matthew Dowst

PoshBytes: Your .NET Path Toolkit for PowerShell

A fast paced walkthrough of the most useful System.IO.Path methods in PowerShell with practical demos and humor. Learn how to extract filenames, change extensions, combine paths, and manage temporary files.

This post is a companion for the video embedded below. Scroll down to see the code from the video.

Getting the File Name

Extract WITHOUT extension

[System.IO.Path]::GetFileName('C:\Reports\yearly.xlsx')

[IO.Path]::GetFileNameWithoutExtension('C:\Data\Q4.xlsx')

Changing File Extensions

Remove extension entirely

[IO.Path]::ChangeExtension('C:\Data\yearly.xlsx', '.bak')

[IO.Path]::ChangeExtension('C:\Data\yearly.xlsx', $null)

Getting Just the Extension

What if the file has MULTIPLE extensions?

[IO.Path]::GetExtension('C:\Data\yearly.xlsx')

[IO.Path]::GetExtension('C:\Data\archive.tar.gz')

Getting the Directory Name

Nested paths behave just fine

[IO.Path]::GetDirectoryName('C:\Data\yearly.xlsx')

[IO.Path]::GetDirectoryName('C:\One\Two\Three\four.txt')

Combining Paths

Combine several parts

[IO.Path]::Combine('C:\Data', 'Reports')

[IO.Path]::Combine('C:\Data', 'Reports', 'Q4', '10k.txt')

Getting the Root Path

[IO.Path]::GetPathRoot('C:\Data\yearly.xlsx')

Checking for Invalid Characters

Check whether a string contains any invalid file name characters

[IO.Path]::GetInvalidFileNameChars() -join('')

[IO.Path]::GetInvalidPathChars() -join('')

('file?name.txt').ToCharArray() |  Where-Object { $_ -in
    [IO.Path]::GetInvalidFileNameChars() } | 
    Foreach-Object{
        Write-Host "Invalid character found $_" -Fore red
    }

Getting a Random Temp File

Get a random file name (no folder implied)

[IO.Path]::GetTempFileName()

[IO.Path]::GetRandomFileName()

Wrap Up

• Extract file names and extensions
• Change or remove extensions
• Get directory, root, and temp paths
• Combine paths safely
• Identify invalid characters
• Generate temp/random file names

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