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. 16-colour terminal protocol: Added in patch 39. 256 colors terminal protocol: Added in patch 111. 88-colour terminal protocol: Added in patch 115. Custom colour 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. See also List of terminal emulators luit, a character set converter invoked automatically by xterm when necessary Vttest, vt100/vt220/xterm test utility References External links Free software programmed in C Free terminal emulators Software using the MIT license X Window programs