How do I run test-path on all paths in the system variable PATH using powershell?

Question

I would like to run the Test-Path, or something similar the completes my purpose to find the invalid paths in my path variable.

The main thing I have done is search for

test path system variable for invalid entries

This did not find anything.

This example is just to show I have tried something, but I don't really know what the best command it.

Test-Path -Path %Path% -PathType Any

Update

These scripts enabled my to find a couple bad paths and fix them

Answer 1

Building on Mathias R. Jessen's great solution in a comment:

# Output those PATH entries that refer to nonexistent dirs.
# Works on both Windows and Unix-like platforms.
$env:PATH -split [IO.Path]::PathSeparator -ne '' |
  Where-Object { -not (Test-Path $_) }

• Using the all uppercase form PATH of the variable name and [IO.Path]::PathSeparator as the separator to -split by makes the command cross-platform:

  • On Unix-like platforms environment variable names are case-sensitive, so using $env:PATH (all-upercase) is required; by contrast, Windows is not case-sensitive, so $env:PATH works there too, even though the actual case of the name is Path.

  • On Unix-like platforms, : separates the entries in $env:PATH, whereas it is ; on Windows - [IO.Path]::PathSeparator returns the platform-appropriate character.

• -ne '' filters out any empty tokens resulting from the -split operation, which could result from directly adjacent separators in the variable value (e.g., ;;) - such empty entries have no effect and can be ignored.

  • Note: With a an array as the LHS, such as returned by -split, PowerShell comparison operators such as -eq and -ne act as filters and return an array of matching items rather than a Boolean - see about_Comparison_Operators.

• The Where-Object call filters the input directory paths down to those that do not exist, and outputs them (which prints to the display by default).

  • Note that, strictly speaking, Test-Path's first positional parameter is -Path, which interprets its argument as a wildcard expression.
  • For full robustness, Test-Path -LiteralPath $_ is needed, to rule out inadvertent interpretation of literal paths that happen to contain [ as wildcards - though with entries in $env:PATH that seems unlikely.