Parameter Checking - Shell Programming and Scripting

ammu · #1 (**permalink**) 05-23-2007

Hi all,

My script has 2 mandatory and 1 optional paramter. If the third parameter(optional) one is null the it should take a default value say 3. Can any one please write a simple code.

sh test.sh 1 2 3

var1=$1
var2=$2

if [ -z $3 ]
then
var3=3
fi

echo " the third variable $var3"

But this is erroring out saying " test.sh: test: argument expected"

Thanks in advance
Ammu

aigles · #2 (**permalink**) 05-23-2007

Code:

var1=$1
var2=$2

if [ -z "$3" ]
then
var3=3
fi

echo " the third variable $var3"

or

Code:

var1=$1
var2=$2
var3=${var3:-3}
echo " the third variable $var3"

Jean-Pierre.

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