Man Linux: Main Page and Category List

NAME

       FbTerm - a fast Frame Buffer based TERMinal emulator for linux

SYNOPSIS

       fbterm [options] [--] [command [arguments]]

DESCRIPTION

       FbTerm  is  a fast terminal emulator for linux with frame buffer device
       or VESA video card. Features include:

         * mostly as fast  as  terminal  of  linux  kernel  while  accelerated
       scrolling is enabled
         *  select  font with fontconfig and draw text with freetype2, same as
       Qt/Gtk+ based GUI apps
         * dynamically create/destroy  up  to  10  windows  initially  running
       default shell
         * record scroll-back history for every window
         *  auto-detect  current  locale  and  convert  text encoding, support
       double width scripts like Chinese, Japanese etc
         * switch between configurable additional text encodings with hot keys
       on the fly
         *  copy/past selected text between windows with mouse when gpm server
       is running
         * change the orientation of screen display, a.k.a. screen rotation
         * lightweight input method framework with client-server architecture
         * background image for eye candy

OPTIONS

       command [arguments] may be given to override  the  built-in  choice  of
       shell  program.  Normally  FbTerm checks the SHELL variable. If that is
       not set, it tries to use the user’s login shell  program  specified  in
       the password file. If that is not set, /bin/sh will be used. You should
       use the -- argument to separate FbTerm’s  options  from  the  arguments
       supplied to the command.

       FbTerm  first  uses  option  value specified in command line arguments,
       then in the configure  file  $HOME/.fbtermrc.   If  that  file  doesn’t
       exist, FbTerm will create it with default options on startup.

       -h, --help
              display the help and exit

       -V, --version
              display FbTerm version and exit

       -v, --verbose
              display extra FbTerm’s information

       -n, --font-names=text
              specify font family names

       -s, --font-size=num
              specify font pixel size

       --font-width=num
              force font width

       -f, --color-foreground=num
              specify foreground color

       -b, --color-background=num
              specify background color

       -e, --text-encodings=text
              specify additional text encodings

       -r, --screen-rotate=num
              specify the orientation of screen display

       -i, --input-method=text
              specify input method program

       --cursor-shape=num
              specify default cursor shape

       --cursor-interval=num
              specify cursor flash interval

       --vesa-mode=num
              specify VESA video mode

       --vesa-mode=list
              display available VESA video modes

       see comments in $HOME/.fbtermrc for details of these options.

SHORTCUT SUMMARY

       keyboard:
         CTRL_ALT_E:    exit from FbTerm
         CTRL_ALT_C:    create a new window
         CTRL_ALT_D:    destroy current window
         CTRL_ALT_1:    switch to window 1
         CTRL_ALT_2:    switch to window 2
         CTRL_ALT_3:    switch to window 3
         CTRL_ALT_4:    switch to window 4
         CTRL_ALT_5:    switch to window 5
         CTRL_ALT_6:    switch to window 6
         CTRL_ALT_7:    switch to window 7
         CTRL_ALT_8:    switch to window 8
         CTRL_ALT_9:    switch to window 9
         CTRL_ALT_0:    switch to window 10
         SHIFT_LEFT:    switch to previous window
         SHIFT_RIGHT:   switch to next window
         SHIFT_PAGEUP:    history scroll up
         SHIFT_PAGEDOWN:  history scroll down
         CTRL_ALT_F1:                 switch to encoding of current locale
         CTRL_ALT_F2 to CTRL_ALT_F6:  switch to additional encodings
         CTRL_SPACE:    toggle input method

       mouse:
         move when left button down:      select text
         double click with left button:   auto select text
         click with right button:         paste selected text

       Sometimes  above  actions  will  not work, please try to redo them with
       shift key holding down.

FRAME BUFFER DEVICE

       Before executing FbTerm, make sure there is a frame  buffer  device  in
       your  system,  and  you  have read/write access right with it. Normally
       FbTerm tries to  open  /dev/fb0  and  /dev/fb/0,  environment  variable
       "FRAMEBUFFER" may be used to override this built-in behavior.

VESA VIDEO DEVICE

       From  version  1.6,  FbTerm  adds  VESA video card support. By default,
       FbTerm tries frame buffer device first, if failure, then tries  to  use
       VESA device with highest resolution and color depth. option "vesa-mode"
       may be given to force only open VESA device with  the  specified  video
       mode.  To see available video modes for your VESA card, execute "fbterm
       --vesa-mode=list".

       Attention: 1) VESA support requires root privilege to work; 2)  do  not
       force  to  use  VESA  device  on  the  system  with frame buffer device
       enabled, they maybe conflict with each other.

FONT

       FbTerm invokes fontconfig to get a font list, if the first font doesn’t
       contain the glyph for the rendering character, it will try second font,
       then the third, ... and so on, user can see this ordered font list with
       "fbterm -v".

       If  you  don’t  like the fonts selected by FbTerm, execute "fc-list" to
       get available fonts, choose favorites as the  value  of  option  "font-
       names".  You  may  also  modify the configure file of fontconfig, which
       will change the behavior of all programs based on fontconfig!

TEXT ENCODING

       By using iconv, FbTerm converts other encodings  to  internal  encoding
       UTF-8.  On  startup,  FbTerm  checks variable LC_CTYPE to determine the
       default text encoding, which is binded to shortcut  CTRL_ALT_F1.   User
       can  specify up to 5 additional encodings with option "text-encodings",
       for example, as a  Chinese  user,  you  set  "text-encodings=gbk,big5",
       shortcut CTRL_ALT_F2 will bind to gbk, and CTRL_ALT_F3 bind to big5.

BACKGROUND IMAGE

       FbTerm  doesn’t  load  and  parse  any  image file with various formats
       directly, instead it takes a screen shot  of  frame  buffer  device  on
       startup  if variable FBTERM_BACKGROUND_IMAGE is defined, then uses this
       screen shot as the background for text rendering. In  order  to  enable
       background image support, user should first put a image to frame buffer
       device with a image viewer. A wrapper script using fbv is listed below:

           #!/bin/bash

           #  fbterm-bi:  a  wrapper  script  to  enable background image with
       fbterm
           # usage: fbterm-bi /path/to/image fbterm-options

           echo -ne "\e[?25l" # hide cursor

           fbv -ciuker "$1" << EOF
           q
           EOF

           shift
           export FBTERM_BACKGROUND_IMAGE=1
           exec fbterm "$@"

       Attention: 1) do not enable background image  on  frame  buffer  device
       with  8bpp  depth,  because  FbTerm changes color map table for correct
       text rendering; 2) if the screen shot is different  from  the  original
       image, try to use a fast scrolling disabled frame buffer device.

INPUT METHOD

       Instead  of  adding  input  method  directly in FbTerm, a client-server
       based input method framework is designed to do this work.  FbTerm  acts
       as  a  client,  standalone  IM  program  as  a  server, and they run in
       separated processes.

       As a normal IM user, you should have a IM program written  for  FbTerm,
       and  specify  it  as the value of option "input-method".  CTRL_SPACE is
       the shortcut to activate/deactivate input method.

SECURITY NOTES

       FbTerm tries to change linux kernel key map table to  setup  shortcuts,
       which requires SYS_TTY_CONFIG capability from kernel version 2.6.15. It
       means FbTerm should be a setuid 0 program to allow  non-root  users  to
       use  shortcuts. FbTerm only switches to root privilege temporarily when
       changing key map table, we believe it’s pretty much free from  security
       problems.

       If  you  really  don’t  like  this and not use VESA support, and have a
       linux kernel with file system capabilities enabled, which allow user to
       give  binaries  a  subset  of  root’s  powers  without  using  setuid 0
       (official kernel 2.6.27 includes it), you can run command "sudo  setcapcap_sys_tty_config+ep/path/to/fbterm".

PERFORMANCE

       According  test  result,  FbTerm  spends more than 95% time on painting
       screen. Speedup painting will significantly increase performance.  Here
       are some suggestions for frame buffer device:

         *  Enable  fast  scrolling on frame buffer device. The visible screen
       will be just a window of the video memory, when scrolling, FbTerm  only
       change the start of window, no need to repaint the whole screen.

         *  On  Intel  P6  family  processors  the Memory Type Range Registers
       (MTRRs) may be used to control processor access to  memory  ranges.  If
       you  have  video  card  on  a  PCI or AGP bus, enabling write-combining
       allows bus write transfers to be combined into a larger transfer before
       bursting  over  the  PCI/AGP  bus.  This  can  increase  performance of
       FbTerm’s paint operations.

       Maybe you need to  enable  them  manually  for  your  video  card.  For
       example, by default fast scrolling and write-combining are all disabled
       on general VESA frame buffer device, GRUB/LILO configure file should be
       modified to enable them.  A GRUB example is showed below:

       title Ubuntu
           root (hd0,0)
           kernel   /boot/vmlinuz   ro   root=LABEL=UBUNTU   splash  vga=0x317
       video=vesafb:ywrap,mtrr:3
           initrd /boot/initrd.img

       You may check fast scrolling status with "fbterm -v",  a  message  with
       "scrolling:   redraw"  means  fast  scrolling  is  disabled,  otherwise
       enabled.

AUTHOR

       Written by dragchan.

REPORTING BUGS

       Please submit bug reports to  <http://code.google.com/p/fbterm/issues>.

COPYRIGHT

       Copyright  ©  2008-2009  dragchan.  License GPLv2: GNU GPL version 2 or
       later <http://gnu.org/licenses/gpl.html>.
       This is free software: you are free  to  change  and  redistribute  it.
       There is NO WARRANTY, to the extent permitted by law.