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Welcome — this lesson explains three common ways to access a Linux system and how to find built-in documentation from the command line. You’ll learn:
  • Local graphical (desktop) login
  • Remote graphical login (RDP from Windows)
  • Remote text-mode login (SSH)
Finally, we’ll cover how to use built-in help: --help, pagers, and man pages. Quick overview Local graphical login If you have a desktop environment installed (for example Ubuntu with GNOME), use the local display manager on the machine:
  1. At the physical machine, pick your username on the login screen.
  2. Enter your password.
  3. After login you’ll see the desktop environment; open a terminal emulator for command-line work.
When finished, use the logout option from the system menu.
A dark GNOME desktop overview with the search box querying "terminal," showing the Terminal app icon and matching results in the center and a left-side dock of app icons. The top bar with the time is visible at the top.
Remote graphical login (RDP from Windows) If you need a remote desktop from a Windows PC, RDP is one option. On the Linux side you must run an RDP server such as xrdp to provide desktop sessions. On Windows, open Remote Desktop Connection (mstsc) and connect to the Linux host IP (for example 10.0.0.81).
  • On first connection you may see a certificate prompt — accept only if you trust the host.
  • Enter your username and password on the remote login screen.
  • The remote desktop appears inside the RDP window; maximize if you’d like a full-screen experience.
Useful links:
When accepting certificates or host warnings, confirm the host identity first. Only accept certificates from hosts you trust to avoid man-in-the-middle risks.
Remote text-mode login (SSH) SSH is the standard way to get a remote shell on Linux servers. It works the same from Windows (PowerShell/Terminal), macOS, and Linux: Basic connection:
On first-time connections you will see an authenticity prompt. Type yes to add the host key to ~/.ssh/known_hosts, then enter your password:
Tip: Use SSH key-based authentication for better security and convenience. Example workflow:
Prefer key-based authentication over passwords. Use ssh-agent and ssh-add to cache keys for sessions and enable two-factor or certificate-based methods for stronger security.
Built-in system documentation Linux provides multiple help sources accessible from the shell. Use the method that fits the level of detail you need. Common help options Quick help with —help Many commands print concise usage and option summaries with --help. For example, to review ls options:
Look for the -l option to use the long listing format. Example excerpt:
Pager behavior and longer help output Long help text is often displayed in a pager (usually less). Navigate with arrow keys, Page Up/Page Down, and press q to exit. Example:
The output may show a pager prompt like lines 1-27 indicating you can scroll. Manual pages (man) Most important commands have a man page. Use man <command> to open a detailed manual:
Man pages are organized with standard sections: NAME, SYNOPSIS, DESCRIPTION, OPTIONS, EXAMPLES, and FILES. Example header from journalctl:
Manual sections and disambiguation Man pages are grouped into numbered sections. Some names appear in multiple sections (e.g., printf as a shell command and as a C library function). To list and understand sections, read the man manual:
Common sections include: If you need the printf command (section 1) rather than the C library function (section 3), specify the section:
Summary This lesson covered local and remote logins (GUI and SSH) and how to access built-in documentation using --help, pagers, and man pages. Use these tools to explore command options and become more effective on Linux systems.
A dark slide with the phrase "Read and Use System Documentation" on the left and a large information ("i") icon inside a rounded square on the right. The layout has a minimal, navy-blue theme with a small KodeKloud logo in the top-right.

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