Advanced Bash−Scripting Guide

#!/bin/bash
# color−echo.sh: Echoing text messages in color.
# Modify this script for your own purposes.
# It's easier than hand−coding color.
black='\E[30;47m'
red='\E[31;47m'
green='\E[32;47m'
yellow='\E[33;47m'
blue='\E[34;47m'
magenta='\E[35;47m'
cyan='\E[36;47m'
white='\E[37;47m'
Advanced Bash−Scripting Guide
alias Reset="tput sgr0"
# Reset text attributes to normal
#+ without clearing screen.
cecho ()
# Color−echo.
# Argument $1 = message
# Argument $2 = color
{
local default_msg="No message passed."
# Doesn't really need to be a local variable.
message=${1:−$default_msg}
color=${2:−$black}
echo −e "$color"
echo "$message"
Reset
# Defaults to default message.
# Defaults to black, if not specified.
# Reset to normal.
}
return
# Now, let's try it out.
# −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−
cecho "Feeling blue..." $blue
cecho "Magenta looks more like purple." $magenta
cecho "Green with envy." $green
cecho "Seeing red?" $red
cecho "Cyan, more familiarly known as aqua." $cyan
cecho "No color passed (defaults to black)."
# Missing $color argument.
cecho "\"Empty\" color passed (defaults to black)." ""
# Empty $color argument.
cecho
# Missing $message and $color arguments.
cecho "" ""
# Empty $message and $color arguments.
# −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−
echo
exit 0
# Exercises:
# −−−−−−−−−
# 1) Add the "bold" attribute to the 'cecho ()' function.
Chapter 34. Miscellany 345