[ 12 September 1999
 The Linux Colours with Linux terminals mini-HOWTO is not being maintained by
 the author any more.  If you are interested in maintaining the
 Colours-ls mini-HOWTO, please get in touch with me at
 <[email protected]>. ]

 Colours with Linux terminals
 Thorbj�rn Ravn Andersen, [email protected]
 v1.4, 7 August 1997

 Most Linux distributions have a 'ls' command for listing the contents
 of a directory that can visually enhance their output by using differ�
 ent colours, but configuring this to taste may not be a trivial task.
 This document explains the various aspects and approaches of altering
 the setup by configuring existing software, plus locations of alterna�
 tive software usually not included with Slackware or RedHat, which may
 be used on most versions of Unix.  The HTML version is also available
 from my own source at <http://www.mip.ou.dk/~ravn/colour-ls>.

 1.  Introduction

 In recent years colour displays have become very common, and users are
 beginning to exploit this by using programs that utilizes colours to
 give quick visual feedback on e.g. reserved keywords in programming
 languages, or instant notification of misspelled words.

 As the Linux text console supports colour, the original GNU ls was
 quickly modified to output colour information and included in
 Slackware around version 2.0.  Improved versions of these patches have
 now migrated into the standard GNU distribution of ls, and should
 therefore be a part of all new Linux distributions by now.

 This revision is an update on a major rewrite from the initial
 release, including information on xterms and kernel patching.

 The information in this document has been confirmed on Redhat 4.1, and
 was originally compiled with the 2.0.2 release of Slackware, and the
 1.1.54 kernel.  The kernel patch information was retrieved on
 slackware 2.2.0 with the 1.2.13 kernel, and tcsh as the default shell,
 and later confirmed with a 2.0.27 kernel.  If you use any other
 configuration, or unix version, I would appreciate a note stating your
 operating system and version, and whether colour support is available
 as standard.

 2.  Quickstart for the impatient

 If you have a new distribution of Linux, do these modifications to
 these files in your home directory.  They take effect after next
 login.

      ~/.bashrc:
          alias ls="ls --color"

      ~/.cshrc:
          alias ls 'ls --color'

 That's it!

 You may also want to do an ``eval `dircolors $HOME/.colourrc`'', to
 get your own colours.  This file is created with ``dircolors -p
 >$HOME/.colourrc'' and is well commented for further editing.

 3.  Do I have it at all?

 First of all you need to know if you have a version of ls which knows
 how to colourize properly.  Try this command in a Linux text console
 (although an xterm will do):

      % ls --color

 (the % is a shell prompt):

 If you get an error message indicating that ls does not understand the
 option, you need to install a new version of the GNU fileutils
 package.  If you do not have an appropriate upgrade package for your
 distribution, just get the latest version from your GNU mirror and
 install directly from source.

 If you do not get an error message, you have a ls which understands
 the command.  Unfortunately, some of the earlier versions included
 previously with Slackware (and possible others) were buggy.  The ls
 included with Redhat 4.1 is version 3.13 which is okay.

      % ls --version
      ls - GNU fileutils-3.13

 If you ran the ``ls -- color'' command on a Linux textbased console,
 the output should have been colourized according to the defaults on
 the system, and you can now decide whether there is anything you want
 to change.

 If you ran it in an xterm, you may or you may not have seen any colour
 changes.  As with ls itself, the original xterm-program did not have
 any support of colour for the programs running inside of it, but
 recent versions do.  If your xterm doesn't support colours, you should
 get a new version as described at the end of this document.  In the
 meantime just switch to textmode and continue from there.

 4.  Which colours is there to choose from?

 This shell script (thanks to the many who sent me bash versions) shows
 all standard colour combinations on the current console.  If no
 colours appear, your console does not support ANSI colour selections.

 #!/bin/bash
 # Display ANSI colours.
 #
 esc="\033["
 echo -n " _ _ _ _ _40 _ _ _ 41_ _ _ _42 _ _ _ 43"
 echo "_ _ _ 44_ _ _ _45 _ _ _ 46_ _ _ _47 _"
 for fore in 30 31 32 33 34 35 36 37; do
   line1="$fore  "
   line2="    "
   for back in 40 41 42 43 44 45 46 47; do
     line1="${line1}${esc}${back};${fore}m Normal  ${esc}0m"
     line2="${line2}${esc}${back};${fore};1m Bold    ${esc}0m"
   done
   echo -e "$line1\n$line2"
 done

 The foreground colour number is listed to the left, and the background
 number in the box.  If you want bold characters you add a "1" to the
 parameters, so bright blue on white would be "37;44;1".  The whole
 ANSI selection sequence is then

 ESC [ 3 7 ; 4 4 ; 1 m

 Note: The background currently cannot be bold, so you cannot have
 yellow (bold brown) as anything but foreground.  This is a hardware
 limitation.

 The colours are:
         0 - black    4 - blue           3# is foreground
         1 - red      5 - magenta        4# is background
         2 - green    6 - cyan
         3 - yellow   7 - white          ;1 is bold

 5.  How to configure colours with ls

 If you wish to modify the standard colour set built into ls, you need
 your personal copy in your home directory, which you get with

       cd ; dircolors -p > .coloursrc

 After modifying this well-commented file you need to have it read into
 the environment string LS_COLORS, which is usually done with

      eval `dircolors .colourrc`

 You need to put this line in your .bashrc/.cshrc/.tcshrc (depending on
 your shell), to have it done at each login.  See the dircolors(1)
 manual page for details.

 6.  How to change the text-mode default from white-on-black

 You will need to tell the terminal driver code that you want another
 default.  There exists no standard way of doing this, but in case of
 Linux you have the setterm program.

 "setterm" uses the information in the terminal database to set the
 attributes.  Selections are done like

      setterm -foreground black -background white -store

 where the "-store" besides the actual change makes it the default for
 the current console as well.  This requires that the current terminal
 (TERM environment variable) is described "well enough" in the termcap
 database.  If setterm for some reason does not work, here are some
 alternatives:

 6.1.  Xterm

 One of these xterms should be available and at least one of them
 support colour.

      xterm -fg white -bg blue4
      color_xterm -fg white -bg blue4
      color-xterm -fg white -bg blue4
      nxterm -fg white -bg blue4

 where 'color_xterm' supports the colour version of 'ls'.  This
 particular choice resembles the colours used on an SGI.

 6.2.  Virtual console.

 You may modify the kernel once and for all, as well as providing a
 run-time default for the virtual consoles with an escape sequence.  I
 recommend the kernel patch if you have compiled your own kernel.

 The kernel source file is /usr/src/linux/drivers/char/console.c around
 line 1940, where you should modify

         def_color       = 0x07;   /* white */
         ulcolor         = 0x0f;   /* bold white */
         halfcolor       = 0x08;   /* grey */

 as appropriate.  I use white on blue with

              def_color       = 0x17;   /* white */
              ulcolor         = 0x1f;   /* bold white */
              halfcolor       = 0x18;   /* grey */

 The numbers are the attribute codes used by the video card in
 hexadecimal: the most significant digit (the "1" in the example
 colours above) is the background; the least significant the
 foreground. 0 = black, 1 = blue, 2 = green, 3 = cyan, 4 = red, 5 =
 purple, 6 = brown/yellow, 7 = white. Add 8 to get "bright" colours.
 Note that, in most cases, a bright background == blinking characters,
 dull background. (From [email protected]
 <mailto:[email protected]>).

 You may also supply a new run-time default for a virtual console, on a
 per-display basis with the non-standard ANSI sequence (found by
 browsing the kernel sources)

              ESC [ 8 ]

 which sets the default to the current fore- and background colours.
 Then the Reset Attributes string (ESC [ m) selects these colours
 instead of white on black.

 You will need to actually echo this string to the console each time
 you reboot.  Depending on what you use your Linux box for, several
 places may be appropriate:

 6.2.1.  /etc/issue

 This is where "Welcome to Linux xx.yy" is displayed under Slackware,
 and that is a good choice for stand-alone equipment (and probably be a
 pestilence for users logging in with telnet).  This file is created at
 boottime (Slackware in /etc/rc.d/rc.S; Redhat in /etc/rc.d/rc.local),
 and you should modify lines looking somewhat like

        echo ""> /etc/issue
        echo Welcome to Linux `/bin/uname -a | /bin/cut -d\  -f3`. >> /etc/issue

 to

   ESCAPE="<replace with a single escape character here>"
   echo "${ESCAPE}[H${ESCAPE}[37;44m${ESCAPE}[8]${ESCAPE}[2J"> /etc/issue
   echo Welcome to Linux `/bin/uname -a | /bin/cut -d\  -f3`. >> /etc/issue

 This code will home the cursor, set the colour (here white on blue),
 save this selection and clean the rest of the screen.  The
 modification takes effect after the next reboot.  Remember to insert
 the _literal_ escape character in the file with C-q in emacs or
 control-v in vi, as apparently the sh used for executing this script
 does not understand the /033 syntax.

 6.2.2.  /etc/profile or .profile

        if [ "$TERM" = "console" ]; then
            echo "\033[37;44m\033[8]" #
      # or use setterm.
            setterm -foreground white -background blue -store
        fi

 6.2.3.  /etc/login or .login

        if ( "$TERM" == "console" ) then
          echo "\033[37;44m\033[8]"
      # or use setterm.
            setterm -foreground white -background blue -store
        endif

 6.3.  Remote login

 You should be able to use the setterm program as shown above.  Again,
 this requires that the remote machine knows enough about your
 terminal, and that the terminal emulator providing the login supports
 colour. In my experience the best vt100 emulation currently available
 for other platforms are:

 �  MS-DOS:         MS-Kermit (free, not a Microsoft product)

 �  Windows 95/NT:  Kermit/95 (shareware)

 �  OS/2:           Kermit/95 (shareware).  Note though that the
    standard telnet understands colours and can be customized locally.

 See  <http://www.columbia.edu/kermit/> for details about Kermit.

 7.  Software

 All the information described here is assuming a GNU/Linux
 installation.  If you have something else (like e.g. a Sun running X
 or so) you can get and compile the actual software yourself.

 The colour version of 'xterm' is based on the standard xterm source
 with a patch available from any X11R6 site.  The xterm distributed
 with R6.3 is rumoured to have native colour support, but is untested
 by me.

      ftp://ftp.denet.dk/pub/X11/contrib/utilities/color-xterm-R6pl5-patch.gz

 See the documentation if you use an older version of X.  Note: I
 haven't tried this myself!

 of the several mirrors.  Get at least version 3.13.

      ftp://ftp.denet.dk/pub/gnu/fileutils-3.XX.tar.gz

 I have myself successfully compiled color-ls on Solaris, SunOS and
 Irix.

 I would appreciate feedback on this text.  My e-mail address is
 [email protected] <mailto:[email protected]>

 --

 Thorbj�rn Ravn Andersen

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