Xterm

{{short description|Standard terminal emulator for the X Window system}}

{{Infobox software

| name = xterm

| logo = Icon of XTerm (from 2012).svg

| screenshot = Xterm.png

| caption = A sample xterm, running the Bash shell, showing a listing of /etc.

| author = Mark Vandevoorde

| developer = Thomas Dickey

| released = {{Start date and age|1984}}

| genre = Terminal emulator

| license = MIT/X Consortium License

| website = {{Official URL}}

| latest release version = {{wikidata|property|edit|reference|P348}}

| latest release date = {{start date and age|{{wikidata|qualifier|P348|P577}}}}

| operating_system = Unix, Unix-like, MVS OpenVMS, OS/2

}}

xterm is the standard terminal emulator for the X Window System. It allows users to run programs which require a command-line interface.

If no particular program is specified, xterm runs the user's shell. An X display can show one or more user's xterm windows output at the same time.{{cite book|isbn=978-0596555191|title=Mac OS X for Unix Geeks (Leopard): Demistifying the Geekier Side of Mac OS X|last1=Rothman|first1=Ernest E|last2=Jepson|first2=Brian|last3=Rosen|first3=Rich|date=2008-09-18|publisher="O'Reilly Media, Inc." }}{{cite book|isbn=978-0789718051|title=The Complete Idiot's Guide to UNIX|last1=Wagner|first1=Bill|year=1998|publisher=Penguin |url-access=registration|url=https://archive.org/details/completeidiots00wagn}} Each xterm window is a separate process, but all share the same keyboard, taking turns as each xterm process acquires focus. Normally focus switches between X applications as the user moves the pointer (e.g., a mouse cursor) about the screen, but xterm provides options to grab focus (the Secure Keyboard feature) as well as accept input events sent without using the keyboard (the Allow SendEvents feature). Those options have limitations, as discussed in the xterm manual.{{cite web |url=https://invisible-island.net/xterm/manpage/xterm.html#h2-SECURITY |title=xterm(1) |at=Security |accessdate=December 21, 2021 }}

XTerm originated prior to the X Window System. It was originally written as a stand-alone terminal emulator for the VAXStation 100 (VS100) by Mark Vandevoorde, a student of Jim Gettys, in the summer of 1984, when work on X started. It rapidly became clear that it would be more useful as part of X than as a standalone program, so it was retargeted to X. As Gettys tells the story, "part of why xterm's internals are so horrifying is that it was originally intended that a single process be able to drive multiple VS100 displays."{{cite web

| url = https://invisible-island.net/xterm/xterm.faq.html#who_did_it

| title = XTerm – Frequently Asked Questions (FAQ), Who wrote XTerm?

| author = Thomas E. Dickey

| access-date = 2018-06-04

| archive-url = https://web.archive.org/web/20180624104926/https://invisible-island.net/xterm/xterm.faq.html#who_did_it

| archive-date = 2018-06-24

| url-status = live}}

After many years as part of the X reference implementation, around 1996 the main line of development then shifted to XFree86 (which itself forked from X11R6.3), and it is now maintained by Thomas Dickey.

Many xterm variants are also available, such as hanterm, a variant tailored to Korean speakers, and kterm, which is designed for Japanese speakers.{{cite web

| url = https://invisible-island.net/xterm/xterm.faq.html#other_versions

| title = XTerm – Frequently Asked Questions (FAQ), What versions are available?

| author = Thomas E. Dickey

| access-date = 2018-06-04

| archive-url = https://web.archive.org/web/20180624104926/https://invisible-island.net/xterm/xterm.faq.html#other_versions

| archive-date = 2018-06-24

| url-status = live}} Most terminal emulators for X started as variations on xterm.{{dubious|most terminal emulators for X|date=July 2024}}{{cite web |url=https://tldp.org/HOWTO/Xterm-Title-6.html |title=How to change the title of an xterm |author=Ric Lister |date=27 October 1999 |at=6. Appendix: escapes for other terminal types}}

Features

=Terminal emulation=

Early versions emulated the VT102 and Tektronix 4014. {{cite web|url=https://invisible-island.net/xterm/xterm.faq.html#what_is_it|title=What is XTerm?|author=Thomas E. Dickey|access-date=2018-06-04|archive-url=https://web.archive.org/web/20180624104926/https://invisible-island.net/xterm/xterm.faq.html#what_is_it|archive-date=2018-06-24|url-status=live}}

Later versions added control sequences for DEC and other terminals such as:

VT220: Added in patch 24.{{Cite web|url=https://invisible-island.net/xterm/xterm.log.html#xterm_24 |title=Patch #24 - 1996/8/11 - XFree86 3.1.2Ee |access-date=2008-02-25 |archive-url=https://web.archive.org/web/20011222194057/http://invisible-island.net/xterm/xterm.log.html#xterm_24 |archive-date=2001-12-22 |url-status=live}} Later, in 1998, xterm added support for VT220 features, such as extending its support of ISO-2022 shift functions to provide the National Replacement Character Set feature.
VT320: Added in patch 24.
VT420: DECSTR (soft terminal reset) was added in patch 34.{{Cite web |url=https://invisible-island.net/xterm/xterm.log.html#xterm_34 |title=Patch #34 - 1997/1/5 - XFree86 3.2o |access-date=2008-02-25 |archive-url=https://web.archive.org/web/20011222194057/http://invisible-island.net/xterm/xterm.log.html#xterm_34 |archive-date=2001-12-22 |url-status=live }} In 2012, xterm's default emulation was changed to VT420 to allow tmux to assume the corresponding left/right margin support.{{Cite web|url=https://invisible-island.net/xterm/xterm.log.html#xterm_280 |title=Patch #280 - 2012/06/24 |access-date=2021-12-21 |archive-url=https://web.archive.org/web/20120926050154/https://invisible-island.net/xterm/xterm.log.html#xterm_280 |archive-date=2012-09-26 |url-status=live}}
VT520: Although not officially emulated, parts of VT520 features were implemented.{{Cite web |url=https://invisible-island.net/xterm/xterm.faq.html#why_not_vt520 |title=Why not emulate VT520? |access-date=2007-01-06 |archive-url=https://web.archive.org/web/20120325084746/http://invisible-island.net/xterm/xterm.faq.html#why_not_vt520 |archive-date=2012-03-25 |url-status=live }} Controls DECSMBV and DECSWBV for setting the margin- and warning-bell volume were added in patch 254.{{Cite web |url=https://invisible-island.net/xterm/xterm.log.html#xterm_254 |title=Patch #254 - 2010/1/6 |access-date=2021-12-21 |archive-url=https://web.archive.org/web/20110412000243/http://invisible-island.net/xterm/xterm.log.html#xterm_254 |archive-date=2011-04-12 |url-status=live }}

=Customization=

Image:XtermMenus.png

Image:Xterm-256color.svg values are shown for each. (Updated 2024)]]

As with most X applications, xterm can be customized via global X resources files (e.g. /usr/lib/X11/app-defaults/XTerm), per-user resource files (e.g. ~/XTerm, ~/.Xresources), or command-line arguments. Most of the command-line options correspond to resource settings, as noted in the manual page.

While the name of the program is xterm, the X resource class is XTerm. The uxterm script overrides this, using the UXTerm resource class.

XTerm normally does not have a menu bar. To access xterm's three menus, users hold the control key and press the left, middle, or right mouse button. Support for a "toolbar" can be compiled-in, which invokes the same menus.

=Protocols=

Supported terminal control functions include:

ANSI X3.64
Sixel
Digital Equipment Corporation VT family:
VT52
VT102
VT220
VT420
Tektronix family:
Tektronix 4014

In addition to protocols used in commercially available terminal machines, xterm added a few protocols that have been adopted by other terminal emulators, such as:

Mouse tracking: Support for buttons 4 and 5 was added in patch 120.{{Cite web|url=https://invisible-island.net/xterm/xterm.log.html#xterm_120 |title=Patch #120 - 1999/10/28 - XFree86 3.9.16c}}
16-color terminal protocol: Added in patch 39.{{Cite web|url=https://invisible-island.net/xterm/xterm.log.html#xterm_39 |title=Patch #39 - 1997/5/24 - XFree86 3.2Xl}}
256 colors terminal protocol: Added in patch 111.{{Cite web|url=https://invisible-island.net/xterm/xterm.log.html#xterm_111 |title=Patch #111 - 1999/7/10 - XFree86 3.9Pw}}
88-color terminal protocol: Added in patch 115.{{Cite web|url=https://invisible-island.net/xterm/xterm.log.html#xterm_115 |title=Patch #115 - 1999/9/18 - XFree86 3.9.16a}}
Custom color palette: Ability to specifying the RGB values for palette entries was added in patch 111.

= Fonts =

Initially Xterm supported only Portable Compiled Format (PCF) bitmap font until 2000 when Xft library was introduced to support modern stroke-based fonts like TrueType.{{Cite web |title=XTERM - Change Log |url=https://invisible-island.net/xterm/xterm.log.html#xterm_148 |access-date=2022-11-17 |website=invisible-island.net}}

References

External links

{{Official website}}

Category:Free software programmed in C

Category:Free terminal emulators

Category:Software using the MIT license

Category:X Window programs