student@ubuntu:~$
shell 1/5 15 XP

Terminal Basics

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Quick Reference

Command What It Does
whoami Print your username
hostname Print the machine’s name
date Print current date and time
cal Print a calendar for the current month
uname -a Print system info (kernel, architecture, etc.)
clear Clear the terminal screen (or Ctrl+L)

Command Structure

command [options] [arguments]
Part Example Role
Command ls The program to run
Options -la Modify behavior (start with -)
Arguments /home What it acts on

The Prompt

student@ubuntu:~$
│       │      │└─ $ = regular user (# = root)
│       │      └── ~ = current directory (home)
│       └────────── hostname
└────────────────── username

How It Works

Terminal
student@ubuntu:~$ whoami
student
student@ubuntu:~$ hostname
ubuntu
student@ubuntu:~$ date
Mon Mar 30 09:15:42 PDT 2026
student@ubuntu:~$ uname -a
Linux ubuntu 6.8.0-31-generic #31-Ubuntu SMP x86_64 GNU/Linux
student@ubuntu:~$ cal
March 2026
Su Mo Tu We Th Fr Sa
1 2 3 4 5 6 7
8 9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31

The shell is a REPL: Read your command, Evaluate (execute) it, Print the result, Loop back for the next one. The default shell on Linux is bash (Bourne Again Shell).

Common Pitfalls

  • Case sensitivity – CAL is not cal. Unix commands are lowercase.
  • Typos get no mercy – the shell won’t guess what you meant. dat is not date.
  • $ vs # – if your prompt shows #, you’re root. Tread carefully.
  • Spaces matter – ls-la is not ls -la. The space separates the command from its options.

Unlocks

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