in the simplest form:

ls . -Filter your_file_or_dir -Recurse

Of course the output can be piped for more magic, eg:

ls . -Filter your_file_or_dir -Recurse | % { $_.FullName }

Breakdown:

• ls (or dir or gci) = alias for Get-ChildItem cmdlet
• . = shorthand for the current directory path
• -Filter = file system path to search for, wildcards are supported
• -Recurse (or -r) = search also the nested directory structure.
• | = pipe which routes the output of the 'ls' cmd to the following expression
• % = shorthand for the foreach-object
• $_ = shorthand for $PSItem = the current argument for the currently executing script block, in this case each file system object that matches the filter