title: PowerShell $_ syntax
body: <p>In <a href="https://stackoverflow.com/a/41836207/2125110">this answer</a> the author proposed the following snippet:</p>
  <pre><code>dir -Path C:\FolderName -Filter *.fileExtension -Recurse | %{$_.FullName}
  </code></pre>
  <p>I can understand the majority of it, but I'm unable to search documentation for the last part. The output of the search is piped <code>|</code> and used in <code>%{}</code> and as <code>$_</code>.</p>
  <p>I have experimented around it, <code>%{}</code> is a for-each statement I believe, <a href="https://www.bing.com/search?q=powershell+%25%7B%7D&amp;qs=n&amp;form=QBRE&amp;sp=-1&amp;pq=powershell+%25%7B&amp;sc=8-13&amp;sk=&amp;cvid=32AE75E1FEB0406FA98C18F9F741FF1F" rel="nofollow noreferrer">bing search was not effective</a>. <code>$_</code> is also somewhat magic: it is a variable, with no name and thus immediately consumed? I don't care much for the <code>.FullName</code>, that part I sorted out. Again, <a href="https://www.bing.com/search?q=powershell+%24_&amp;qs=n&amp;form=QBRE&amp;sp=-1&amp;pq=powershell+%24_&amp;sc=1-13&amp;sk=&amp;cvid=D62C3EA028ED4E1393BEE779E7CB9F9B" rel="nofollow noreferrer">bing search was not effective</a>, nor searching for those char sequences in PowerShell docs.</p>
  <p>Can anybody explain it to me?</p>