> For the complete documentation index, see [llms.txt](https://microway.gitbook.io/hpc-test-drive/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://microway.gitbook.io/hpc-test-drive/logging_in.md).

# Logging In

## Command Line Interface (CLI)

On most HPC clusters, users access the system via a text-based command line interface (CLI). Typically, command line access is provided via an encrypted, secure shell (SSH). The command line provides a powerful and flexible interface into the cluster - though there is a learning curve.

![Example of a command line](https://4192192950-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LP6FqhFTk0yl2rn1Osm%2F-LP6FtRHi71hG7N7eQ8y%2F-LP6GF9FnTdWHw3g1r1W%2Fexample_command_line.png?generation=1539867749278641\&alt=media)

Mac and Linux computers include built-in support for the command line. Windows computers are supported, too, although a shell client program must be installed.

## Graphical Interface (GUI)

It is also possible to access the cluster via a GUI. The GUI provides a more familiar interface to beginners. It also allows usage of advanced tools, such as graphical debuggers and performance profilers.

![Access to a Linux cluster from a Windows desktop](https://4192192950-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LP6FqhFTk0yl2rn1Osm%2F-LP6FtRHi71hG7N7eQ8y%2F-LP6GF9Hw7-Y02gDOS-H%2FWindows7_accessing_HPC_Cluster_via_NoMachine.png?generation=1539867748659058\&alt=media)

Microway recommends NoMachine for responsive, enterprise-class GUI connections to clusters. Some HPC administrators may also configure VNC, Remote Desktop, X-Win32, or X-Windows tunneling through SSH connections.

The following sections describe the various ways to login to our Test Drive cluster.