Linux Shell -- case statement

The case statementthe case statement is good alternative to multilevel if-then-else-fi statement. It enable you to match several
Values against one variable. Its easier to read and write. Syntax:

           case  $variable-name  in                pattern1)   command                                ...                                ..                                command;;                pattern2)   command                                ...                                ..                                command;;                patternN)   command                                ...                                ..                                command;;                *)             command                                ...                                ..                                command;;           esac

The $ variable-name is
Compared against the patterns until a match is found. the shell then executes all the statements up to the two semicolons that are next to each other. the default is *) and its executed if no match is found. for e.g. write script as follows:
#
if no vehicle name is given
# i.e. -z $1 is defined and it is NULL
#
# if no command line arg

if [ -z $1 ]
then
  rental="*** Unknown vehicle ***"
elif [ -n $1 ]
then
# otherwise make first arg as rental
  rental=$1
fi

case $rental in
   "car") echo "For $rental Rs.20 per k/m";;
   "van") echo "For $rental Rs.10 per k/m";;
   "jeep") echo "For $rental Rs.5 per k/m";;
   "bicycle") echo "For $rental 20 paisa per k/m";;
   *) echo "Sorry, I can not gat a $rental for you";;
esac

First script will check, that if $1 (First Command Line argument) is given or not, if not given set value of Marshal
Variable to "*** unknown vehicle ***", if command line Arg is supplied/Given Set Value of variable Al variable to given value (command line Arg ). the $ specified Al is compared against the patterns until a match is found.
For first test run its match with Van and it will show output"
Van Rs.10 per K/M ."
For second test run it print,"
Car Rs.20 per K/m ".
And for last run, there is no match for Maruti-800, hence default I. e. *) is executed and it prints, "Sorry,
I can not gat A Maruti-800 for you ".
Note that
Esac is always required to indicate end of case statement.