OS - Terminal (Emulator) (Term|tty)
Table of Contents
1 - About
A terminal is a media using a fixed-pitch character grid such as:
- teletypes,
- portable devices with limited display capabilities
- bank terminal
- text based such as console
- but also graphical interfaces.
A terminal introduces the context of output where to draw and/or write data.
This article talks about text terminal.
A terminal emulator, terminal application, term, or tty (teletypewriter), is a program that emulates a terminal.
2 - Articles Related
3 - features
Example:
- Native Windows user interface with a simple options dialog.
- Easy copy & paste.
- Drag & drop of text, files and folders.
- Ability to open files and URLs with Ctrl+click.
- Comprehensive character encoding support, including UTF-8.
- Wide character display and Windows IME support.
- Window transparency, including glass effect on Vista and 7.
- 256 colours.
- Fullscreen mode.
- Options stored in a text file. No registry entries.
- Small program size and quick scrolling.
4 - Text
The role of a text terminal (emulate process or not) is to interact with the user:
- to feed text input to the master pseudo-device for use by the shell (which is connected to the slave pseudo-device)
- and to read text output from the master pseudo-device and show it to the user.
The terminal emulator must also handle terminal control commands, e.g., for resizing the screen.
A terminal window allows the user access to a text terminal and all its applications such as:
- and text user interface (TUI) applications.
When user starts terminal, it runs generally by default a OS Shell or a console application (cli).
5 - Locality
5.1 - Local
A local terminal is also known as a console window.
On Unix-like operating systems, it is common to have one or more terminal windows connected to the local machine.
5.2 - Remote
Remote terminals connect to remote hosts to run applications remotely.
The terminal may run on a remote machine via:
- ssh,
- or dial-up.
6 - List
- iTerm2,
- konsole,
- guake,
7 - Escape sequences
Terminals usually support a sequence of characters called an escape sequences for controlling color, cursor position, etc.
7.1 - Color
See Terminal - Color
8 - Terminal emulator
8.1 - Local login
- GNOME Terminal,
- Konsole
- and Mac OS X Terminal.
8.2 - Remote Login
Remote login handlers such as ssh and telnet servers play the same role but communicate with a remote user instead of a local one.
8.3 - With session context
Screen and Tmux are used to add a session context to a pseudo terminal. For example, it provides terminal persistence allowing to disconnect from one computer and connect later on from another computer on the net.
the Linux console behaves almost like a vt100 terminal
Pseudo-Terminal
PuTTY is an example of a virtual terminal.
Virtual Terminal (VT) series:
Many terminal emulators have been developed for terminals such as:
- vt53,
- vt102,
- vt320,
- vt420
- etc.
If not, screen implements a superset of vt100 and vt100 is universal
pseudo-terminal normal login session
if the current session has no tty