Mr N

The directory lister under UNIX is called ls. In the deep and distant past this was a very black and white affair. GNU has changed all that by introducing an environment variable called LS_COLORS which allows you to set the colours of files based on extension, permissions and file type.

As usual the instructions on how to configure it are locked away so that only a privileged few know how to configure them. When I started looking for this holy grail, I came across some poor guy who had worked it out through trial and error. I thought that there must be some documentation, somewhere on the internet. But, no! I have pieced together all the information I could find from mail list postings, support forums and when I eventually found it, the source code.

I will attempt to describe what I have discovered on my journey so that others may start from here with a better understanding of how LS_COLORS works.

The BSD implementation of ls used in BSD, FreeBSD and MacOS is slightly different. It uses a set or unset CLICOLOR environment variable or the ls command line switch -G to indicate whether to use the colours defined in the environment variable LSCOLORS. Whereas GNU's ls uses the command line switch −−colour and the environment variable LS_COLORS instead (Thanks Gilles).

If you do not specify a colour to use then the default will be used, which is why unsetting LS_COLORS has no visible effect. The defaults can be obtained by running the dircolors command

dircolors --print-database

which gives you

LS_COLORS='rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.lz=01;31:*.xz=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.rar=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.jpg=01;35:*.jpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.axv=01;35:*.anx=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:*.axa=00;36:*.oga=00;36:*.spx=00;36:*.xspf=00;36:';
export LS_COLORS

The database in question is a globally readable file which can be overridden depending on your terminal type. The database file is initially set to /etc/DIR_COLORS then overridden with one of the following. The first being the least precedent and the last being the most.

• /etc/DIR_COLORS.$TERM
• /etc/DIR_COLORS.$TERM
• $HOME/.dircolors
• $HOME/.dircolors.$TERM
• $HOME/.dir_colors
• $HOME/.dir_colors.$TERM

This configuration file has several options:

• COLOR - ether:
  • tty (add colour to ls when output is on the command line)
  • all (all colours to ls on the command line and when piping i.e. ls > file.txt will have colour coding information in it)
  • none (switch off)
• OPTIONS - strictly not related to LS_COLORS. This allows you to add extra options to the ls command.
• TERM - one line per terminal type that supports colour.
• EIGHTBIT - 1 (on) or 0 (off) to allow 8-bit output.
• and finally the colour definitions for file type and file extensions.

On most systems the ls command has been aliased to use the coloured option by default:

alias "ls=ls --color=auto"

The LS_COLORS environment variable is a colon separated list of key=colour pairs. There are 2 types of key: file types and file extensions.

Below is a list of all the keys (that I know of!). Thanks to Bartman for his starter page.

Key	/etc/DIR_COLORS name	Notes
no	NORMAL, NORM	Global default, although everything should be something
fi	FILE	Normal file
di	DIR	Directory
ln	SYMLINK, LINK, LNK	Symbolic link. If you set this to 'target' instead of a numerical value, the colour is as for the file pointed to.
pi	FIFO, PIPE	Named pipe
do	DOOR	Door
bd	BLOCK, BLK	Block device
cd	CHAR, CHR	Character device
or	ORPHAN	Symbolic link pointing to a non-existent file
so	SOCK	Socket
su	SETUID	File that is setuid (u+s)
sg	SETGID	File that is setgid (g+s)
tw	STICKY_OTHER_WRITABLE	Directory that is sticky and other-writable (+t,o+w)
ow	OTHER_WRITABLE	Directory that is other-writable (o+w) and not sticky
st	STICKY	Directory with the sticky bit set (+t) and not other-writable
ex	EXEC	Executable file (i.e. has 'x' set in permissions)
mi	MISSING	Non-existent file pointed to by a symbolic link (visible when you type ls -l)
lc	LEFTCODE, LEFT	Opening terminal code
rc	RIGHTCODE, RIGHT	Closing terminal code
ec	ENDCODE, END	Non-filename text
*.extension		Every file using this extension e.g. *.jpg

The keys (above) are assigned a colour pattern which is a semi-colon separated list of colour codes.

Effects

Code	Property
00	Default colour
01	Bold
04	Underlined
05	Flashing text
07	Reversetd
08	Concealed

Colours

Code	Property
30	Black
31	Red
32	Green
33	Orange
34	Blue
35	Purple
36	Cyan
37	Grey

Backgrounds

Code	Property
40	Black background
41	Red background
42	Green background
43	Orange background
44	Blue background
45	Purple background
46	Cyan background
47	Grey background

Extra colours

Code	Property
90	Dark grey
91	Light red
92	Light green
93	Yellow
94	Light blue
95	Light purple
96	Turquoise
97	White
100	Dark grey background
101	Light red background
102	Light green background
103	Yellow background
104	Light blue background
105	Light purple background
106	Turquoise background
107	White background

Most of the defaults are all right and not really worth changing. By default, executable directories show up as white on a light green background and normal directories which are blue on a black background. Both of these settings make your eyes go funny! So here is how to change just them.

LS_COLORS="ow=01;90:di=01;90"
export LS_COLORS

The above snippet changes both directories colours to grey.

Just as an aside, the easiest way to remap your colours is via the client control interface. I use PuTTY which allows you to redefine the terminal colour settings, but I think I'll save that for another block entry!

A while ago I wrote an article called Training SpamAssassin, Horde, IMAP, Plesk user configuration which describes how to integrate Spam Assassin user learning and Plesk's installation of Horde mail client.

Sam left a comment suggesting that I tell Horde about the good work I have done - so I did! Opened an enhancement bug request and after a bit of a chat they agreed to put my changes into IMP 4.2. Hurray!

I'll wait for 4.2 release then update my original article.

Broadband suppliers don’t go out of their way to advising the fact they have problems. So if you are ever looking for their service page to tell you why you can’t see anything in Germany, then look no further. This list I hope will turn into the definitive list of the locations of broadband service pages. So if you know any drop me a line: British Telecom (BT) Service status update: Broadband http://btbusiness.custhelp.com/app/service_status Centric Telecom http://www.centrictelecom.com/support-networkstatus.php Google http://www.google.com/appsstatus TalkTalk Broadband and telephone https://www.talktalk.co.uk/talktalk/servlet/gben-server-PageServer?article=MAIN.UK.TALKTALK.STATIC.OUTAGES http://www.talktalkmembers.com/content/view/51/121/ Virgin Service status: cable customers http://status-cable.virginmedia.com/vmstatus/summary.do Service status: non-cable customers http://gps.virgin.net/service-announcements/status Speed test: http://www.vmspeed.com/ Zen Internet http://status.zensupport.co.uk/ Thinking of changing, then find out which service providers are close to you. http://www.samknows.com/broadband/exchange_search

DD-WRT is an open source router firmware based on Linux. The open source community realised that Linksys had used GPL licenced code to build the firmware of their WRT54 home market routers. The community partitioned Linksys to release the software code they had written in order to compile with the terms of the GPL.

Unusually, Linksys open sourced all the software and not just the sections which used the GPL licence, and thus the DD-WRT project was born. It's aim is to turn a £60 router into a £600 router, for as many routers as it can.

DD-WRT's website has thousands of pages of documentation, but it seems to be lacking the bit which tells you how and where to get the bit you want. So here it is. The instructions below tell you how to find out which version you need to download for your particular hardware type.

On the bottom of the router there is a panel which lists the model number and version. Goto the DD-WRT Supported Devices page and match the model to a Hardware type and hardware version.

1. Various sizing restrictions mean that on some routers you may not be able to install the full version so make a note of the DD-WRT version required column.
2. The File Version pages tells you what the file names mean. In most cases you want the standard version.
3. Go to DD-WRT's download area.
4. Choose whether you would like stable or release candidates: stable usually means 'the old version' and release candidate means 'newer, but a bit untested'. I usually go for a release candidate for the new features. If you feel the need you can report bugs back to the project.
5. Select the version number.
6. Earlier you made a note of the hardware type from the supported devices list, so select that type now.
7. Earlier you made a note of the manufacturer from the supported devices list, so select that type now.
8. Select the model number of your router and the version number (from the under side of the router).
9. Select the File Version usually dd-wrt.v24_std_generic.bin.

Now, you can follow their instructions to do the installation.

I was looking for an on-line Bandwidth Calculator to find out how many megabytes there were in 100 megabits. Simple I know but hay! I found quite a few, but unfortunately they were all rubbish! I was surprised how many bad implementations there were, some even submitted the form to the remote web server for it to work out. What a waste! Anyway after trawling the wastelands, I decided to write my own.

'B' indicates bytes and 'b' indicates bits so for example, if you want to find out how many megabytes of transfer you can get from a 100 megabit network card then:

1. Enter 100 in the In unit box.
2. Select Mb from the In unit drop down.
3. Select MB from the Out unit drop down.

Unfortunately, I have not figured out how to embed Javascript in a blog page, so here is the Bandwidth Calculator in action. For completeness the code is listed below.

<html>
<body>

<script language="Javascript">
//<!--
// This code was written by BigSoft Limited.
// Please include this message when you use the code in any form.
// (c) BigSoft Limited 2008
// MIT License
//
function recalc()
{
  var frm = document.forms['converter'];
  var in_val = frm.in.value;
  var in_unit = frm.inunit.options[frm.inunit.selectedIndex].value;
  var out_unit = frm.outunit.options[frm.outunit.selectedIndex].value;

  // convert in to bits
  var bits;
  switch (in_unit)
  {
    case 'b' : bits = in_val                                ; break;
    case 'B' : bits = in_val * 8                            ; break;
    case 'Kb': bits = in_val * 1024                         ; break;
    case 'KB': bits = in_val * 1024 * 8                     ; break;
    case 'Mb': bits = in_val * 1024 * 1024                  ; break;
    case 'MB': bits = in_val * 1024 * 1024 * 8              ; break;
    case 'Gb': bits = in_val * 1024 * 1024 * 1024           ; break;
    case 'GB': bits = in_val * 1024 * 1024 * 1024 * 8       ; break;
    case 'Tb': bits = in_val * 1024 * 1024 * 1024 * 1024    ; break;
    case 'TB': bits = in_val * 1024 * 1024 * 1024 * 1024 * 8; break;
  }

  // convert bits to required unit
  var answer;
  switch (out_unit)
  {
    case 'b' : answer = bits                                ; break;
    case 'B' : answer = bits / 8                            ; break;
    case 'Kb': answer = bits / 1024                         ; break;
    case 'KB': answer = bits / 1024 / 8                     ; break;
    case 'Mb': answer = bits / 1024 / 1024                  ; break;
    case 'MB': answer = bits / 1024 / 1024 / 8              ; break;
    case 'Gb': answer = bits / 1024 / 1024 / 1024           ; break;
    case 'GB': answer = bits / 1024 / 1024 / 1024 / 8       ; break;
    case 'Tb': answer = bits / 1024 / 1024 / 1024 / 1024    ; break;
    case 'TB': answer = bits / 1024 / 1024 / 1024 / 1024 / 8; break;
  }
  frm.out.value = answer;
}
// -->
</script>

<form name="converter">
<table>
<tr>
 <td>In unit</td>
 <td><input name="in" value="0" onChange="recalc();">
<select name="inunit" onChange="recalc()">
<option value="b">b</option>
<option value="B">B</option>
<option value="Kb">Kb</option>
<option value="KB">KB</option>
<option value="Mb">Mb</option>
<option value="MB">MB</option>
<option value="Gb">Gb</option>
<option value="GB">GB</option>
<option value="Tb">Tb</option>
<option value="TB">TB</option>
</select>
</td></tr>
<tr>
 <td>Out unit</td>
 <td><input name="out" value="0"  onFocus="blur();">
<select name="outunit" onChange="recalc();">
<option value="b">b</option>
<option value="B">B</option>
<option value="Kb">Kb</option>
<option value="KB">KB</option>
<option value="Mb">Mb</option>
<option value="MB">MB</option>
<option value="Gb">Gb</option>
<option value="GB">GB</option>
<option value="Tb">Tb</option>
<option value="TB">TB</option>
</select>
</td>
</tr>
</table></form>
</body>
</html>