uterm(1) start script for a Unicode capable terminal window

SYNTAX

uterm [ -terminal-options ] [ -e program arguments ... ]

uterm [ -rx | -rxvt ] [ -rxvt-options ] [ -e program arguments ... ]
uterm [ -xt | -xterm ] [ -xterm-options ] [ -e program arguments ... ]

DESCRIPTION

Invoke a terminal window with a reasonably optimised range of Unicode support, enforcing UTF-8 mode and using the best Unicode fonts found. Many systems are not yet properly configured to enable easy and straight-forward use of Unicode in a text-mode terminal environment (such as xterm or rxvt). The purpose of uterm is to help users to start a terminal with good Unicode capabilities without much hassle.

Terminal selection

Either of xterm or rxvt-unicode is selected as the terminal application to start, depending on:
  • Availability of rxvt-unicode: The script checks whether rxvt-unicode is available under the name urxvt (e.g. on cygwin), or if rxvt is available, whether it actually is rxvt-unicode (and not an older version). Only if this check is positive, rxvt is considered.
  • User preference, implicit: If the environment variable TERM starts with "rxvt", rxvt-unicode is preferred.
  • User preference, explicit: With the command line option --rx or -rxvt, rxvt-unicode is preferred. With -xt or -xterm, xterm is preferred.
  • Font selection: If the GNU unifont is selected, rxvt is chosen.
  • In all other cases, xterm is chosen.
Users of mlterm are assumed to start mlterm themselves directly, so mlterm is not considered. Neither of KDE konsole or gnome-terminal is currently considered since they cannot be font-configured on-the-fly.

Font selection

The uterm script tries its best to use fonts that provide a maximum of Unicode support.
  • First it checks if you have the 10x20 Unicode font and a matching 20x20 double width font installed (see explanation below about CJK coverage).
  • If not, it checks if you have the 9x18 Unicode font and a matching 18x18 double width font installed and uses them.
  • If both are not found, it tries to invoke rxvt with the GNU unifont.
  • If either GNU unifont or rxvt are not installed, efont is tried.
  • As a last resort, it tries to invoke xterm with 6x13 and 12x13 fonts.
  • As a very last fallback, it invokes xterm with its configured default fonts.

Note: The efonts are installed on fewer systems than the misc-fixed fonts so only 1 size of them is considered and at a lower priority. If you prefer efont, you should configure xterm font usage yourself (using X resource configuration) and invoke xterm directly.
Note: GNU unifont does unfortunately not work with xterm (or rather xterm with GNU unifont), so in this case rxvt is invoked.

Information about font usage

Font selection is a matter of both taste and script coverage. The uterm script uses fonts with a good coverage of Unicode script ranges, but its order of precedence may not suit your specific needs. In that case you should configure your exact desired font preference and invoke the desired terminal (xterm, rxvt) directly. Coverage of certain scripts would suggest certain font preferences: Korean Hangul: GNU unifont Devanagari: efont Georgian: efont, misc X fonts
    ...

CJK coverage and the 10x20 fonts

Among the Unicode "misc" X fonts (misc-fixed-...), the 20 pixel size fonts are much clearer in appearance than the 18 pixel fonts for which CJK wide fonts (using double cell width in a fixed-width terminal) are available. Unfortunately, xterm is not yet capable of padding an 18x18 font up to 20x20 pixel character cells for use together with a 10x20 pixel font. The bdf18to20 script, packaged with the mined editor like uterm, helps with this issue and generates the missing fonts from the 18 pixel double width fonts by padding blank pixels. If you have installed those, uterm will select 20 pixel fonts as its first preference.
Note: 20x20 fonts (padded with bdf18to20) are already installed as part of the xterm package with SuSE Linux 10.0.
Note: The 6x13 pixel font from Unicode misc-fixed-... also has a matching 12x13 CJK font but that size is really much too small for serious application on modern desktops which often provide higher resolutions than traditional workstations.

UTF-8 environment setup

The uterm script enforces UTF-8 mode with the terminal and also sets up the locale variable environment to reflect UTF-8 terminal encoding. If necessary, all LC_* and LANG environment variables are modified to provide a proper environment for applications started inside the Unicode terminal. (See the inline documentation of the uterm script for how this is done.)

X resource class

When starting xterm, uterm uses the X resource class UXTerm so you can configure the desired appearance of UTF-8 mode terminal windows in your X resource configuration. For rxvt-unicode, the class URxvt can be used for X resources.

Unicode width data version

If called with an -e option to invoke a specific program in it, uterm enables the -mk_width option of xterm (if xterm version 201 or newer is available). This tells xterm to use its own, compiled-in character width property tables, rather than using system locale information. The advantage is that this information is often newer (referring to a newer version of Unicode) than the installed system data. Thus the user is enabled to use up-to-date Unicode data by using a self-installed copy of xterm, rather than being stuck with the Unicode data that the system administrator cares to install. This is especially useful if the application is known to be able to recognise that Unicode version, like the Unicode editor mined. The umined script makes use of this feature to invoke mined in a Unicode terminal with a maximum of Unicode support.

Keyboard resources for application use

If called with an -e option to invoke a specific program in it, uterm also enables a number of other xterm resources in order to enable best keyboard and terminal control for applications:
*VT100*eightBitOutput:true
to enable 8 Bit output (actually not needed in UTF-8 mode)
*VT100*metaSendsEscape:true
to enable ESC prefixing triggered by Alt-key
*VT100*eightBitInput:false
to enable ESC prefixing triggered by Alt-key in old xterm versions
*VT100*deleteIsDEL:true
to enable distinguishing the two DEL keys on the keyboard
*utf8Title:true
to enable UTF-8 window title strings

FILES

$HOME/.Xdefaults or $HOME/.Xresources
typical location of user's X resource configuration

AUTHOR

The uterm script is an auxiliary script packaged with the mined editor by Thomas Wolff. Please send comments, suggestions, bug reports to [email protected].

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