TTYSessions

Working with TTY sessions

This page was last updated on February 11, 2019.

Table of Contents

• Introduction
• Acknowledgements
• Caution
• About TTY sessions
• Working With TTY sessions
  • Choose a TTY session
  • Open a TTY session
    • Open a TTY terminal session
    • Open a TTY GUI session
  • Manage TTY sessions
  • Close a TTY session
    • Close a TTY terminal session
    • Close a TTY GUI session
• Printable Cheat Sheet
• Appendix
• Obligatory Happy Ending

Introduction

• Impatient? Don’t want to read a bunch of stuff? Get right to it!
• You may run into a situation where you need to accomplish a task and someone helpful suggests that you open a TTY session to get the job done. Usually this person will tell you how to open such a session and accomplish your task, but not how to get back out of the session when you’re finished.
• This guide hopes to shed some light on what these sessions are and how to access, use, and get back out of them.
• The use of “Ubuntu” in this guide includes its derivatives (flavors).

Caution

The default TTY session numbers below are for Ubuntu and its derivatives. If you use a different operating system, please check its release notes or check with its support team for the structure of its TTY sessions, compare them with the information in this page, and make adjustments to the steps below before proceeding.

Acknowledgements

I would like to thank John F. Morse for explaining TTY sessions to me in the first place, and Frank Pirrone for contributing the “What is the history of TTY?” section to this document.

About TTY sessions

What does TTY mean?

TTY means the use of a keyboard, mouse, or other hardware to interact with an application on a computer.

What does session mean?

A session is the period of time spent interacting with an application on a computer.

What are TTY sessions?

• A TTY session is the environment you are in while interacting with your computer. To put it more graphically, when you open a TTY session, you’re running what can basically be understood as a copy of Ubuntu.
• Ubuntu installs 7 sessions onto your computer by default.
• All 7 sessions are loaded every time you boot up Ubuntu.
• Each session is independent of the other sessions.
• Sessions opened by the same user can interact with each other. For example, a file created in one session will be visible and accessible in other sessions the user has open.
• Each session has a login, so different users can be logged into the same computer under different sessions at the same time.
• Each session has an address by which it is known to Ubuntu
• Ubuntu reserves one of these addresses for the default session.
• You use the default session every time you boot into Ubuntu.
• You are free to use the other 6 sessions at any time.
• All of the sessions work the same way. You can use any or all of them.
• See the Appendix for the history of TTY.

What are TTY sessions really called?

A more technically correct name for these sessions would be “virtual console” or “virtual terminal,” but since they’re more frequently referred to as “multiple TTY session,” and since their addresses are represented by device special files /dev/tty1 through /dev/tty7, this document uses “multiple TTY session” or “TTY session” when discussing them.

Why do I need multiple TTY sessions?

• If you run into trouble and need to accomplish a task, and a helpful person suggests using a TTY session to accomplish the task, you’ll need to know how to work with multiple TTY sessions.
• If another user wishes to log in to the computer you’re currently using and you don’t wish to stop what you’re doing or log out, you can use multiple TTY sessions. Up to 7 different users can be logged into the same computer at the same time.
• If you’re experiencing a minor lockup, but still have use of the keyboard, you might be able to use another TTY session to “come in from behind” and debug and/or fix the lockup.
• Perhaps you have tasks that you regularly perform, like recording music, editing videos, creating web pages, etc. If you’d like to define sessions which load up the applications needed for those tasks in separate sessions, multiple TTY sessions would be very useful. Such use is outside the scope of this document, but you can do further research on how it’s done by typing man xinit or man startx in a terminal window.

Working With TTY sessions

Choose a session

Before you begin, you must choose a session to open.

• The sessions you can choose from:
• <Ctrl><Alt><F1>
• <Ctrl><Alt><F2>
• <Ctrl><Alt><F3>
• <Ctrl><Alt><F4>
• <Ctrl><Alt><F5>
• <Ctrl><Alt><F6>
• The sessions you cannot choose from:
• The address of the default session in Ubuntu is always <Ctrl><Alt><F7>. Since this is used by Ubuntu, you may not open a new session at this address.
• If a session is currently open at any of the 6 addresses listed above, you cannot open a new session at that address until that session is closed.

Open a session

Each session will open in terminal mode. You can use it as is or load the GUI. This section includes instructions for both.

Open a TTY terminal session

1. Open a new TTY session by pressing these three keys at the same time:

   <Ctrl><Alt><F#>

   Replace # with the session number you’d like to open.

2. Enter your user name and password.
3. Use the terminal session just as you would any other terminal.

Open a TTY GUI session

1. Open a new TTY session by pressing these three keys at the same time:

   <Ctrl><Alt><F#>

   Replace # with the session number you’d like to open.

2. Enter your user name and password.
3. Start the GUI by typing this command:

   startx

   Note that in Ubuntu and its derivatives, startx — :0 is reserved for use by the system for the default GUI session.

4. Press the Enter key.
5. Use the GUI as you normally would.

Manage sessions

• Keep an eye on things:

  • Check what’s happening in which session. In a GUI TTY session, open a terminal window to enter this command. If you’re in a terminal TTY session, you can enter the command at the prompt. Type:

    w

• Switch from the new session to the default session:

  • Press these three keys at the same time:

    <Ctrl><Alt><F7>

• Switch from the default session to the new session:

  • Replace # in the following command with the session number you have open. Press these three keys at the same time:

    <Ctrl><Alt><F#>

• Switch to other sessions

  • Switch to other sessions by pressing the three keys that correspond to each session’s address. You can switch back and forth between sessions as much as you like.

Close a session

Close a TTY terminal session

1. Log out of the session by typing this command:

   exit

2. Press the Enter key.
3. Return to your default session by pressing these three keys at the same time:

   <Ctrl><Alt><F7>

Close a TTY GUI session

1. Use your GUI menu to log out of the GUI normally. This will bring you back to the terminal prompt for your TTY session.
2. Log out of the TTY session by typing this command:

   exit

3. Press the Enter key.
4. Return to your default session by pressing these three keys at the same time:

   <Ctrl><Alt><F7>

Printable Cheat Sheet

Here is a cheat sheet to print out for quick reference.

Appendix

What is the history of TTY?

TTY stands for TeleTYpe, a very old piece of equipment used to interact with computers before monitors and keyboards were developed. The operator sat at a large mechanical typing console with a box of pin-feed paper attached. What was typed and sent to the computer was visible in the same area where typing was seen on a conventional typewriter. When Enter or Enter and Carriage Return was pressed the command was sent to the mainframe or the minicomputer, and the output or response from the computer would appear typed out back on the TTY.

The reader may have seen this technology in movies set in that period, and the experience was even carried on with television displays typically known as CRT after the Cathode Ray Tube that displayed the image. In this example, the computers output or response was shown on the screen appearing one character at a time, often accompanied by the sound of a mechanical TTY. That depiction was largely fictitious and meant to be a dramatic portrayal of a person interacting with a computer.

Continuing this capability but brought up to date on current computers, particularly those running Unix or Linux operating systems, one will find Command Line Interface or CLI screens where following logging in, the operator types commands or multiple commands strung together either by hand or from a file known as a script that contains that string already typed and saved.

This capability is also found in the Graphic User Interface or GUI environment where windows can be opened on the screen looking like contained smaller versions of the full-screen CLI.

In each case, this command environment is called a TTY, or more specifically a PTTY for Pseudo teletype indicating that it’s simply a duplication of the functionality provided by those early devices.

— by Frank Pirrone 

Obligatory Happy Ending

And they all lived happily ever after. The end.