====== Change / Setup bash custom prompt (PS1) ======

===== History commands =====

Add history with a timestamp and increase history commands size, for example in /etc/bashrc or ~root/.bash_profile:
  export HISTSIZE=10000
  export HISTTIMEFORMAT="%F %T   "

===== Prompt =====

http://www.ibm.com/developerworks/linux/library/l-tip-prompt/

http://www.cyberciti.biz/tips/howto-linux-unix-bash-shell-setup-prompt.html

http://www.understudy.net/custom.html

So when executing interactively, bash displays the primary prompt PS1 when it is ready to read a command, and the secondary prompt PS2 when it needs more input to complete a command. Bash allows these prompt strings to be customized by inserting a number of backslash-escaped special characters that are decoded as follows:

^Sequence^Description^
|\a|The ASCII bell character (you can also type \007)|
|\d|the date in "Weekday Month Date" format (e.g., "Tue May 26")|
|\D{format}|the format is passed to strftime(3) and the result is inserted into the prompt string; an empty format results in a locale-specific time representation. The braces are required|
|\e|an ASCII escape character (you can also type \033)|
|\h|First part of hostname (such as "mybox")|
|\H|Full hostname (such as "mybox.mydomain.com")|
|\j|The number of processes you've suspended in this shell by hitting CTRL+Z|
|\l|the basename of the shell’s terminal device name (such as "ttyp4")|
|\n|newline|
|\r|carriage return|
|\s|The name of the shell executable (such as "bash")|
|\t|the current time in 24-hour HH:MM:SS format|
|\T|the current time in 12-hour HH:MM:SS format|
|\@|the current time in 12-hour am/pm format|
|\A|the current time in 24-hour HH:MM format|
|\u|the username of the current user|
|\v|the version of bash (e.g., 2.04)|
|\V|Bash version, including patchlevel|
|\w|the current working directory, with $HOME abbreviated with a tilde|
|\W|the basename of the current working directory, with $HOME abbreviated with a tilde|
|\!|Current command's position in the history buffer|
|\#|Command number (this will count up at each prompt, as long as you type something)|
|\$|if the effective UID is 0, a #, otherwise a $|
|\nnn|Command number (this will count up at each prompt, as long as you type something)|
|\\|a backslash|
|\[|begin a sequence of non-printing characters, which could be used to embed a terminal control sequence into the prompt|
|\]|end a sequence of non-printing characters|

**A list of handy tput command line options**
    tput bold - Bold effect
    tput rev - Display inverse colors
    tput sgr0 - Reset everything
    tput setaf {CODE}- Set foreground color, see color {CODE} table below for more information.
    tput setab {CODE}- Set background color, see color {CODE} table below for more information.

Various color codes for the tput command
^Color {code}^Color^
|0|Black|
|1|Red|
|2|Green|
|3|Yellow|
|4|Blue|
|5|Magenta|
|6|Cyan|
|7|White|

Let us try to set the prompt so that it can display today’d date and hostname:
  PS1="\d \h $ "
Output:
  Sat Jun 02 server $ 

Now setup prompt to display date/time, hostname and current directory:
  $ PS1="[\d \t \u@\h:\w ] $ "
Output:
  [Sat Jun 02 14:24:12 vivek@server:~ ] $

Append the code as follows
<code>
# If id command returns zero, you’ve root access.
if [ $(id -u) -eq 0 ];
then # you are root, set red colour prompt
  PS1="\\[$(tput setaf 1)\\]\\u@\\h:\\w #\\[$(tput sgr0)\\]"
else # normal
  PS1="[\\u@\\h:\\w] $"
fi
</code>

Other samples:
  export PS1='\[33[0;32m\][\u@\h \W]\$\[33[0m\] '
  export PS1="\[\e[0;31m\][\u@\h \w]\$ \[\e[m\]"
  export PS1="\e[0;31m[\u@\h \W]\$ \e[m "
  export PS1=’\[\e[0;32m\]\u@\h:\w\$ \[\e[0m\]’
  export PS1="\[$(tput setaf 1)\]\u@\h:\w $ \[$(tput sgr0)\]"