Test-Path can be used to determine if files or directories exist. In this example, True is returned because file C:\Users\JohnDoe\example.txt does exist.

C:\Users\JohnDoe> Test-Path -Path 'C:\Users\JohnDoe\example.txt'
True

In this example, False is returned because file C:\Users\JohnDoe\bogus.txt does NOT exist.

C:\Users\JohnDoe> Test-Path -Path 'C:\Users\JohnDoe\bogus.txt'
False

In this example, True is returned because directory C:\Users\JohnDoe does exist.

C:\Users\JohnDoe> Test-Path -Path 'C:\Users\JohnDoe'
True

In this example, False is returned because directory C:\Users\bogus does NOT exist.

C:\Users\JohnDoe> Test-Path -Path 'C:\Users\bogus'
False

This is often used with an if statement to do something based on whether or not the file or directory exists.

if (Test-Path -Path 'C:\Users\JohnDoe\example.txt') {
    Write-Host "example.txt exists"
}
else {
    Write-Host "example.txt does NOT exist"
}