Shell – How to change default fonts for a shell

The TERM variable stores the name of an entry in the terminfo database that helps the OS determine how to display information to your terminal. What it defaults to depends entirely on how you've logged in.

Usually, "the console" means you're physically at the computer, logging into one of the text-based virtual terminals (VT1-6).

• TERM defaults to linux (this may differ between distributions; vt100 is a safe alternative)

  • To change this, on Ubuntu 9.10, you'll need to tweak the getty command defined in /etc/init/tty1.conf. That will change the setting for /dev/tty1 (VT1), and you'll need to make the same changes in /etc/init/tty2.conf, ..tty3.conf, etc to get the other virtual terminals as well.

    # original getty command in /etc/init/tty1.conf
    exec /sbin/getty -8 38400 tty1
    
    # new command; sets default TERM on /dev/tty1 to "foobar"
    exec /sbin/getty -8 38400 tty1 foobar
    

If you're logged into X/Gnome/KDE (VT7, 8, or 9), you're not using a console, at least in this context. Technically this is logging into X and using a pseudo-terminal via a terminal emulator application -- that's what gives you the window that shows your shell & commandline.

• TERM is initially set by your terminal emulator. It can be modified in your shell startup files (~/.bashrc, ~/.profile, etc).

  • xterm, rxvt, xterm-color, xterm-256color are all common values

  • To change this value, consult the documentation for your terminal emulator. For example, if using rxvt-unicode (aka urxvt), you'd use the -tn termname commandline option.

If you're logged in remotely (via SSH or remote X), you're definitely not using a console in any context; again, you're using a pseudo-terminal.

• TERM is inherited by the program that started SSH:
  • SSH from a linux virtual terminal results in a remote TERM of linux;
  • SSH from a commandline in an X-windows terminal emulator results in a remote TERM of whatever TERM was set to prior to the SSH command;
  • SSH from a Windows system using PuTTY defaults to xterm, but this can be changed in PuTTY's configuration;
  • and any of the above settings can be overridden by the shell startup files of the remote user.

1. It's an X logical font description, used mostly by pure-Xlib programs.

2. "9x15bold" is a convenience alias for a bitmap font that comes with X.org. It doesn't mean anything specific, there's simply a "fonts.alias" table that translates it to an XLFD:

   ! $Xorg: fonts.alias,v 1.3 2000/08/21 16:42:31 coskrey Exp $
   fixed        -misc-fixed-medium-r-semicondensed--13-120-75-75-c-60-iso8859-1
   variable     -*-helvetica-bold-r-normal-*-*-120-*-*-*-*-iso8859-1
   5x7          -misc-fixed-medium-r-normal--7-70-75-75-c-50-iso8859-1
   ...
   8x16         -sony-fixed-medium-r-normal--16-120-100-100-c-80-iso8859-1
   9x15         -misc-fixed-medium-r-normal--15-140-75-75-c-90-iso8859-1
   9x15bold     -misc-fixed-bold-r-normal--15-140-75-75-c-90-iso8859-1
   10x20        -misc-fixed-medium-r-normal--20-200-75-75-c-100-iso8859-1
   ...
   

3. Xresources is the conventional way. Or at least, used to be. For example, one could set the font for one program with URxvt.font, or for everything with *font, and this would affect all programs – including even those run on a remote server. (X11 is a network protocol.)

   Most newly-written programs use systems such as dconf in GNOME, which is fine, because they were written specifically for GNOME. Xterm, however, is desktop environment-agnostic, because – most importantly – it was created long before KDE and GNOME and Qt and GTK; it is part of the core X11 software suite. Thus it sticks to Xresources because it's simple and standard, with no dependencies on third-party libraries or services. (It has its disadvantages, of course, such as the lack of real-time reconfiguration.)

4. Xterm is a pure Xlib program and uses the font rendering provided by X11, while GNOME Terminal, being written with GTK, uses Freetype (via Pango).

   However, recent versions of Xterm and URxvt include support for basic Freetype font rendering via Xft (has less features than Pango, e.g. lacks font fallback, but often is "good enough"). You can use it by adding these resources:

   URxvt.font: xft:DejaVu Sans Mono:size=9
   
   XTerm*faceName: DejaVu Sans Mono
   XTerm*faceSize: 9
   

   Font size is in points (not pixels).