Advanced Bash−Scripting Guide

# Accept upper or lowercase input.
echo
echo "Roland Evans"
echo "4321 Floppy Dr."
echo "Hardscrabble, CO 80753"
echo "(303) 734−9874"
echo "(303) 734−9892 fax"
echo "revans@zzy.net"
echo "Business partner & old friend"
;;
# Note double semicolon to terminate each option.
"J" | "j" )
echo
echo "Mildred Jones"
echo "249 E. 7th St., Apt. 19"
echo "New York, NY 10009"
echo "(212) 533−2814"
echo "(212) 533−9972 fax"
echo "milliej@loisaida.com"
echo "Girlfriend"
echo "Birthday: Feb. 11"
;;
# Add info for Smith & Zane later.
* )
# Default option.
# Empty input (hitting RETURN) fits here, too.
echo
echo "Not yet in database."
;;
esac
echo
# Exercise:
# −−−−−−−−
# Change the script so it accepts continuous input,
#+ instead of terminating after displaying just one address.
exit 0
Advanced Bash−Scripting Guide
An exceptionally clever use of case involves testing for command−line parameters.
#! /bin/bash
case "$1" in
"") echo "Usage: ${0##*/} "; exit 65;; # No command−line parameters,
# or first parameter empty.
# Note that ${0##*/} is ${var##pattern} param substitution. Net result is $0.
−*) FILENAME=./$1;;
# If filename passed as argument ($1) starts with a dash,
# replace it with ./$1
# so further commands don't interpret it as an option.
* ) FILENAME=$1;; # Otherwise, $1.
esac
Chapter 10. Loops and Branches 119