Linux Commands

This page gives an introduction to the basics of Linux Commands. A more comprehensive guide to the many available Linux commands is available.

We also have three guides/cheat sheets that may be useful to you while using the system and we recommend you bookmarking or printing out and keeping available: Getting Started Reference Sheet (PDF), Shared Computing Cluster Usage Cheat Sheet (PDF), and Linux Guide for SCC Users (PDF)

In addition to this page, we also have a page on Navigating the Linux File System with information on common Linux commands for working with files.

Linux Commands Overview

Once logged into the Shared Computing Cluster (SCC), you will be in a terminal window. You will see a command prompt which allows you to type Linux commands. The program you interact with is called the Linux “shell“. Using the shell, you will communicate with the operating system and filesystem using “commands“.

Command Prompt

After connecting to the Shared Computing Cluster and opening a shell (command window), you will be presented with a command prompt. This can look different depending on the shell. The default shell is called “bash” and for most users it will look as follows.

[username@scc1 ~]$

Regardless of your shell, your interaction with the cluster will be nearly identical. This prompt lets you type in Linux commands to the system to create directories, list files, and do more complex things like run applications. Make sure to hit the “Enter” key after typing in any Linux command.

If your command prompt looks significantly different than normal, this will usually mean that you are inside some specific application and the commands available will be specific to that application, not the standard Linux commands listed on this page.

Commands, Arguments and Options

• Commands are issued to the system by typing in the terminal; some are straightforward and are entered as is.

  # whoami simply returns the username of the current user.
  [username@scc1 ~]$ whoami
  username
  

• Arguments are given to some commands to specify what the command should do something to or with. Often arguments are filenames (that the command will work with) or text (that the command will use).

  # echo takes an "argument" and returns it to the screen (stdout).
  [username@scc1 ~]$ echo "Hello"
  Hello
  

• Options instruct a command to perform a task in different ways. To use these expanded functions, you use the same command and specify different “options.” Options are usually preceeded by a dash (-) or double-dash (–) if a full word is used.

  # hostname returns the name of the system you are currently using. The -f "option" returns the full name (including bu.edu).
  [username@scc1 ~]$ hostname -f
  scc1.bu.edu
  

• Most commands have a manual page that can be accessed using the “man” command.

  [username@scc1 ~]$ man hostname
  

  Note: “q” quits the manual pager.