Colorizing your terminal and shell environment?

Here are a couple of things you can do:

Editors + Code
A lot of editors have syntax highlighting support. vim and emacs have it on by default. You can also enable it under nano.

You can also syntax highlight code on the terminal by using Pygments as a command-line tool.

grep
grep --color=auto highlights all matches. You can also use export GREP_OPTIONS='--color=auto' to make it persistent without an alias. If you use --color=always, it'll use colour even when piping, which confuses things.

ls

ls --color=always

Colors specified by:

export LS_COLORS='rs=0:di=01;34:ln=01;36:mh=00:pi=40;33'

(hint: dircolors can be helpful)

PS1
You can set your PS1 (shell prompt) to use colours. For example:

PS1='\e[33;1m\u@\h: \e[31m\W\e[0m\$ '

Will produce a PS1 like:

[yellow]lucas@ubuntu: [red]~[normal]$

You can get really creative with this. As an idea:

PS1='\e[s\e[0;0H\e[1;33m\h    \t\n\e[1;32mThis is my computer\e[u[\u@\h:  \w]\$ '

Puts a bar at the top of your terminal with some random info. (For best results, also use alias clear="echo -e '\e[2J\n\n'".)

Getting Rid of Escape Sequences

If something is stuck outputting colour when you don't want it to, I use this sed line to strip the escape sequences:

sed "s/\[^[[0-9;]*[a-zA-Z]//gi"

If you want a more authentic experience, you can also get rid of lines starting with \e[8m, which instructs the terminal to hide the text. (Not widely supported.)

sed "s/^\[^[8m.*$//gi"

Also note that those ^[s should be actual, literal ^[s. You can type them by pressing ^V^[ in bash, that is Ctrl + V, Ctrl + [.

I also use:

export TERM=xterm-color
export GREP_OPTIONS='--color=auto' GREP_COLOR='1;32'
export CLICOLOR=1
export LSCOLORS=ExFxCxDxBxegedabagacad

And if you like colorizing your prompt, defined color vars can be useful:

export COLOR_NC='\e[0m' # No Color
export COLOR_BLACK='\e[0;30m'
export COLOR_GRAY='\e[1;30m'
export COLOR_RED='\e[0;31m'
export COLOR_LIGHT_RED='\e[1;31m'
export COLOR_GREEN='\e[0;32m'
export COLOR_LIGHT_GREEN='\e[1;32m'
export COLOR_BROWN='\e[0;33m'
export COLOR_YELLOW='\e[1;33m'
export COLOR_BLUE='\e[0;34m'
export COLOR_LIGHT_BLUE='\e[1;34m'
export COLOR_PURPLE='\e[0;35m'
export COLOR_LIGHT_PURPLE='\e[1;35m'
export COLOR_CYAN='\e[0;36m'
export COLOR_LIGHT_CYAN='\e[1;36m'
export COLOR_LIGHT_GRAY='\e[0;37m'
export COLOR_WHITE='\e[1;37m'

And then my prompt is something like this:

case $TERM in
     xterm*|rxvt*)
         local TITLEBAR='\[\033]0;\u ${NEW_PWD}\007\]'
          ;;
     *)
         local TITLEBAR=""
          ;;
    esac

local UC=$COLOR_WHITE               # user's color
[ $UID -eq "0" ] && UC=$COLOR_RED   # root's color

PS1="$TITLEBAR\n\[${UC}\]\u \[${COLOR_LIGHT_BLUE}\]\${PWD} \[${COLOR_BLACK}\]\$(vcprompt) \n\[${COLOR_LIGHT_GREEN}\]→\[${COLOR_NC}\] "  

$(vcprompt) is calling a python script in my ~/sbin which prints version control information about the current path. It includes support for Mercurial, Git, Svn, Cvs, etc. The author of the script has the source here.

This is the full source of my prompt configuration:

grep and ls have already been mentioned, if you want a lot more colors check out Generic Coloriser, its initial purpose was to colorize logfiles, but right out of the box it also colorizes ping, traceroute, gcc, make, netstat, diff, last, ldap, and cvs.

It's easily extended if you know regexes. I've added ps and nmap to the list (if you get into grc I'll be more than glad to share the .conf files for those two tools)

(Btw, to install it via synaptic, pacman, and alike you might have better luck searching for "grc")