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I spend most of my time working in Unix environments and using terminal emulators. I try to use color on the command-lin, because color makes the output more useful and intuitive.

What are some good ways to add color to my terminal environment? What tricks do you use? What pitfalls have you encountered?

Unfortunately support for color is wildly variable depending on terminal type, OS, TERM setting, utility, buggy implementations, etc.

Here's are some tips from my setup, after a lot of experimentation:

  1. I tend to set TERM=xterm-color, which is supported on most hosts (but not all).
  2. I work on a number of different hosts, different OS versions, etc. I use everything from MacOSX, Ubuntu Linux, RHEL/CentOS/Scientific Linux and FreeBSD. I'm trying to keep things simple and generic, if possible.
  3. I do a bunch of work using GNU screen, which adds another layer of fun.
  4. Many OSs set things like dircolors and by default, and I don't want to modify this on a hundred different hosts. So I try to stick with the defaults. Instead tweak my terminal's color configuration.
  5. Use color for some unix commands (ls, grep, less, vim) and the Bash prompt. These commands seem to the standard "ANSI escape sequences". For example:

    alias less='less --RAW-CONTROL-CHARS'
    export LS_OPTS='--color=auto'
    alias ls='ls ${LS_OPTS}
    

I'll post my .bashrc and answer my own question Jeopardy Style.

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I am shamelessly copying this question from superuser.com, because I never got a good response there, and Superuser isn't specific to Un*x. –  Stefan Lasiewski Aug 10 '10 at 21:21
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8 Answers

up vote 35 down vote accepted

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.

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+[.

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The first PS1 line should read like this: PS1='\e[33;1m\u@\h: \e[31m\W\e[0m\$ '. There is a superfluous x after the fourth backslash. –  Chris May 23 '13 at 7:30
    
@Chris: Quite right, thanks. –  Lucas Jones May 23 '13 at 17:34
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Escapes should be enclosed in \[...\] or else commands in second line will overwrite the first line. PS1='[\e[33;1m]\u@\h: [\e[31m]\W\e[0m\$ ' –  yanglifu90 Aug 29 '13 at 19:09
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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_WHITE='\e[1;37m'
export COLOR_BLACK='\e[0;30m'
export COLOR_BLUE='\e[0;34m'
export COLOR_LIGHT_BLUE='\e[1;34m'
export COLOR_GREEN='\e[0;32m'
export COLOR_LIGHT_GREEN='\e[1;32m'
export COLOR_CYAN='\e[0;36m'
export COLOR_LIGHT_CYAN='\e[1;36m'
export COLOR_RED='\e[0;31m'
export COLOR_LIGHT_RED='\e[1;31m'
export COLOR_PURPLE='\e[0;35m'
export COLOR_LIGHT_PURPLE='\e[1;35m'
export COLOR_BROWN='\e[0;33m'
export COLOR_YELLOW='\e[1;33m'
export COLOR_GRAY='\e[0;30m'
export COLOR_LIGHT_GRAY='\e[0;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.

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See here for the solution to a line problem I got when I used the above PS1: stackoverflow.com/questions/5087036/… –  thoughtadvances Sep 10 '12 at 15:53
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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")

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Set a bold/colored prompt. From cyberciti.biz and the BashFAQ

# 'tput bold' will work regardless of the foreground and background colors.
# Place the tput output into variables, so they are only execd once.
bold=$(tput bold) # This could also be a color.
reset=$(tput sgr0)
export PS1="\u@\[$bold\]\h\[$reset\]:\w \$ "

I've also managed to find color settings which are widely supported, and which don't print gobbledygook characters in older environments (even FreeBSD4!), and seems to work fine if TERM=vt100, xterm, xterm-color. (For the most part). From my .bashrc:

# Set some options, based on the OS
OS=`uname -s` 

case "$OS" in
    "SunOS" ) 
        # Solaris ls doesn't allow color, so use special characters
        LS_OPTS='-F'
        alias  ls='ls ${LS_OPTS}'
        ;;
    "Linux" )
        # GNU ls supports colors!
        # See dircolors to customize colors
        export LS_OPTS='--color=auto' 
        alias  ls='ls ${LS_OPTS}'

        # Get color support for 'less'
        export LESS="--RAW-CONTROL-CHARS"

        # Use colors for less, man, etc.
        [[ -f ~/.LESS_TERMCAP ]] && . ~/.LESS_TERMCAP

        export GREP_OPTIONS="--color=auto"

        ;;
    "Darwin"|"FreeBSD")

        # Most FreeBSD & Apple Darwin supports colors
        export CLICOLOR=true
        # Get color support for 'less'
        export LESS="--RAW-CONTROL-CHARS"

        # Use colors for less, man, etc.
        [[ -f ~/.LESS_TERMCAP ]] && . ~/.LESS_TERMCAP

        export GREP_OPTIONS="--color=auto"
        ;;
    * ) 
        echo "Unknown OS [$OS]"
        ;;
esac
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Or if you want to use ZSH, Phil Gold's prompt at aperiodic.net/phil/prompt is a work of art. –  tsvallender Aug 12 '10 at 9:27
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Some text decoration (bold) to easily differentiate between root and non-root shell. For Zsh:

if test $UID = 0
    then PS1="%B${PS1}%b "
fi

For Bash:

if test $UID = 0
    then PS1="\033[1m${PS1}\033[0m"
fi
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Please specify your shell. The question's only shell specific tag is bash, but I feel your code is not bash. –  manatwork Jan 26 '12 at 9:21
    
@manatwork: sorry, forgot to mention that it was Zsh. Updated my post. –  Mischa Arefiev Jan 26 '12 at 9:53
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I just wondered the same thing. I have my own approach, but I'm looking for alternatives.

I write bash wrappers around program calls and pipe their output though sed. What I like about sed is that it will modify and echo each line right away => not much buffering. However, I dislike that for every call to a wrapped program the sed code is parsed and compiled.

For example this is what I do to color the output of ip:

#
# Colorcodes
#
NORMAL=`echo -e '\033[0m'`
RED=`echo -e '\033[31m'`
GREEN=`echo -e '\033[0;32m'`
LGREEN=`echo -e '\033[1;32m'`
BLUE=`echo -e '\033[0;34m'`
LBLUE=`echo -e '\033[1;34m'`
YELLOW=`echo -e '\033[0;33m'`


#
# command: ip
# highlight ip addresses, default route and interface names
#

IP4=$GREEN
IP6=$LBLUE
IFACE=${YELLOW}
DEFAULT_ROUTE=$LBLUE

IP_CMD=$(which ip)

function colored_ip()
{
${IP_CMD} $@ | sed \
    -e "s/inet [^ ]\+ /${IP4}&${NORMAL}/g"\
    -e "s/inet6 [^ ]\+ /${IP6}&${NORMAL}/g"\
    -e "s/^default via .*$/${DEFAULT_ROUTE}&${NORMAL}/"\
    -e "s/^\([0-9]\+: \+\)\([^ \t]\+\)/\1${IFACE}\2${NORMAL}/"
}

alias ip='colored_ip'
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There's a good tool for setting up your colours for the ls command - http://geoff.greer.fm/lscolors/

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You can try a project that helps on colorizing scripts output also, its named ScriptEchoColor at source forge: http://scriptechocolor.sourceforge.net/

ex.:

echoc "@{lr}text output in light red"
echoc "@{bLGu}text outpus in blue, light green background and underlined"
echoc "you @{lr} can @{bLGu} mix @{-a} it all too"
echoc -x "ls" #executes ls command and colorizes it automatically to be easy to be seen

The automatic colors are configurable.

It still misses a deb package and some more improvements tho.

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