Terminaltyp

Terminaltyp, often referred to as terminal type, is a classification used by software to describe the capabilities of a terminal or terminal emulator. The type informs programs how to render text, move the cursor, and interpret input by selecting the appropriate control sequences and feature sets.

Historically, the concept emerged with early interactive terminals such as DEC’s VT100. As software ran on diverse devices, standardized descriptions of terminal capabilities were developed, notably the termcap and terminfo databases. The TERM environment variable communicates the current terminal type to applications, enabling them to adapt behavior without hardcoding specifics.

Terminfo and termcap describe capabilities through boolean, numeric, and string entries. Boolean capabilities indicate support for features (such as automatic wrap or color), numeric entries store values like number of columns and lines, and string entries hold escape sequences for actions such as moving the cursor, clearing the screen, or changing text attributes. Applications query these databases via libraries (for example, ncurses) or system interfaces. Tools such as tput emit terminal sequences, and infocmp inspects the stored capabilities.

Common terminal types include historical examples like vt100 and ANSI terminals, as well as modern terminal emulators such as xterm, GNOME Terminal, and iTerm2. Extensions like xterm-256color or screen-256color expand color and capability support. The TERM value should accurately reflect the terminal to ensure correct behavior; a mismatched type can lead to garbled output or missing features, affecting portability across environments.

See also: TERM environment variable, terminfo, termcap, ANSI escape codes, terminal emulator.