Linux System Administration for Beginners

Essential Commands

Log into local amp remote graphical and text mode consoles

In this guide, you’ll learn how to authenticate to a Linux system both locally and remotely, using graphical and text-mode interfaces. We’ll experiment with commands first, then explain the concepts behind each method.

Overview of Linux Login Methods

Login MethodInterface TypeLocal/RemoteExample Command
Local Graphical-ModeGUI login screenLocalN/A
Local Text-ModeVirtual terminalLocalN/A
Remote Graphical-ModeVNC / RDP clientRemotevncviewer server_ip:1
Remote Text-Mode (SSH)SSH terminalRemotessh user@server_ip

The image illustrates four login methods: local text-mode console, remote text-mode login, local graphical-mode console, and remote graphical-mode login. Each method is represented with icons and labels.


Console vs. Terminal Emulator

You may see these terms used interchangeably, but they refer to different layers:

  • Console
    Historically a physical keyboard + monitor connected directly to the machine. Today, it’s the text interface you see during boot or on Ctrl+Alt+F* screens.
  • Virtual Terminal (VT)
    A software-only console session you switch to via Ctrl+Alt+F1–F6 (or F7 for GUI).
  • Terminal Emulator
    A graphical application (e.g., GNOME Terminal, Konsole, Windows Terminal) that mimics console behavior in a window.

When Linux boots, systemd and the kernel log messages to the console:

[  OK  ] Mounted Mount unit for snapd, revision 13270.
[  OK  ] Reached target Local File Systems.
[   7.055053] cloud-init[655]: Cloud-init v.21.2 running 'init-local'
[  OK  ] Started Network Services.

Switching to a Virtual Terminal

  1. Press Ctrl+Alt+F2 to open vt2.
  2. You’ll see a login prompt:
CentOS Linux 8
Kernel 4.18.0-305.19.1.el8_4.x86_64 on an x86_64
Activate the web console with: systemctl enable --now cockpit.socket
centos-vm login: _
  1. Enter your username and password.

1. Local Graphical-Mode Console

On desktop distributions with a GUI (GNOME, KDE, etc.), you’ll be greeted by a graphical login manager (GDM, SDDM, LightDM):

The image shows a CentOS login screen with a list of user accounts, highlighting the user "Aaron." It is labeled "Local GUI" at the top.

  1. Select your username.
  2. Enter your password.
  3. You’re now logged into your desktop session.

To log out, use the GUI menu or exit your terminal emulator:

exit

2. Local Text-Mode Console

Server installations often omit the GUI. Instead, you log in on a virtual terminal:

CentOS Stream 8
Kernel 4.18.0-338.el8.x86_64 on an x86_64

Activate the web console with: systemctl enable --now cockpit.socket

LFCS-CentOS login: aaron
Password: 

Password characters are not echoed for security.
After your work, type exit to log out of that VT session.


3. Remote Graphical-Mode Console

Remote desktop requires server-side support. Common options:

  • VNC (Virtual Network Computing)
    • Servers: TigerVNC, RealVNC
    • Clients: vncviewer server_ip:1
  • RDP (Remote Desktop Protocol)
    • Servers: xrdp
    • Clients: Windows Remote Desktop, rdesktop, xfreerdp

Tip

Ensure the appropriate ports are open (e.g., TCP 5900 for VNC, TCP 3389 for RDP) and secured with strong passwords or SSH tunnels.


4. Remote Text-Mode Login (SSH)

Secure Shell (SSH) is the de facto standard for remote Linux administration. It encrypts all data, unlike Telnet.

The image illustrates remote text-mode login methods, comparing SSH (Secure SHell) with a secure connection and Telnet with an unsecured connection.

Finding Your Server’s IP Address

On the server or VM, run:

ip a

Look for the inet entry on your network interface, for example:

2: enp0s3: <...> mtu 1500
    inet 192.168.0.17/24 brd 192.168.0.255 scope global dynamic enp0s3

Here, the IP address is 192.168.0.17.

Connecting with SSH

On Linux or macOS, open a terminal. On Windows 10+, use Command Prompt or PowerShell:

ssh [email protected]

You’ll be prompted for your password:

[email protected]'s password:
Activate the web console with: systemctl enable --now cockpit.socket

Last login: Tue Oct 19 20:27:15 2021 from 192.168.0.3
[aaron@LFCS-CentOS ~]$

Replace aaron and 192.168.0.17 with your own username and server address.

Warning

Never use Telnet for remote administration; it transmits credentials in plaintext. Always prefer SSH or tunneled VNC/RDP.


Next Steps

Practice each login method to get comfortable with Linux consoles. For more details:

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