# Understanding the Command Line Interface

Almost all usage of the Flight system takes place via the Linux command line. For unfamiliar users here is a brief description of it.

[flight@chead1 (mycluster1) folder]$ echo Hello World!
Hello World!

• flight is the name of the user.
• chead1 is the node the user is currently on.
• (mycluster1) is the name of the cluster being used.
• folder is the directory the user is currently in. If this is a ~ then that means you are in your home directory.
• $ indicates whether the user is a root user or normal user (root users see a #).
• echo Hello World! is a command that prints out "Hello World!". This is where commands you type will go.

[username@node (clustername) folder]$ command

If some things that you see here are missing from your command line, you may not have activated Flight.

Here is an example of a Linux Command Line Interface (CLI) without Flight enabled:

[username@node folder]$ command