Shell Programming and Scripting

test.sh -p (protocol) -i (address) -d (directory)

#!/bin/bash
while getopts p:i:d: opt
do
    case $opt in
        p)      protocol="$OPTARG";;
        i)      address="$OPTARG";;
        d)      directory="$OPTARG";;
        ?)      bad=1;;
    esac
done

echo "protcol   -> $protocol" ;
echo "addres    -> $address" ;
echo "directory -> $directory" ;
..........
..............

# ./test.sh -p TCP -i 10.100.100.100 -d /tmp/
protcol   -> TCP
addres    -> 10.100.100.100
directory -> /tmp/

./test.sh -p TCP -i 10.100.100.100 -d /tmp/

in the first while loop OPTARG equals to "TCP" and opt equals to p (so protocol value = "TCP" in the case loop)
second while loop OPTARG equals to "10.100.100.100" and opt equals to i ( address value = "10.100.100.100" in the case loop)
last while loop OPTARG equals to "/tmp/" and opt equals to d (directory value = "/tmp/" in the case loop)

test.sh -i 10.10.10.10 -p tcp -d /tmp

#!/bin/sh

while [ "$#" -gt 0 ]
do
        case "$1" in
        -p) PROTOCOL=$2 ; shift ;;
        -i) IP=$2 ; shift ;;
        -d) DIR=$2 ; shift ;;
        *) break ;;
        esac

        shift
done