How to pass args into scripts?

Question

I am trying to pass arg to this scripts but it does not work anyone knows how fix this ? and I do not want to use args i want to use getopts

For This part

# Get command line parameters
i=
a=
y=
while getopts iay: name
        case $name in
                i) i="$OPTARG" ;;
                a) a="$OPTARG" ;;
                y) y="$OPTARG" ;;
        ?) exit;;
        esac
done

This is the scripts

if [ $# -ne 3 ]
        then
                echo -e "\nUsage: mortgage rate amount period\n"
                exit 1
        fi
# Get command line parameters
i=
a=
y=
while getopts iay: name
        case $name in
                i) i="$OPTARG" ;;
                a) a="$OPTARG" ;;
                y) y="$OPTARG" ;;
        ?) exit;;
        esac
done

# Compute the monthly payment
x=$(echo "scale=20;1+$i/200" | bc)
z=$(echo "scale=20;1/6" | bc)
x2z=$(echo "scale=20;e($z*l($x))" | bc -l)
y12=$(echo "scale=20;-$y*12" | bc)
x2z2y12=$(echo "scale=20;e($y12*l($x2z))" | bc -l)
p=$(echo "scale=3;$a*(($x2z-1))/(1-$x2z2y12)" | bc)

# Print the monthly payment
echo $p
exit 0

========================== This is original scripts:

if [ $# -ne 3 ] then echo -e "\nUsage: mortgage rate amount period\n" exit 1 fi

Get command line parameters

i=$1; a=$2; y=$3

Compute the monthly payment

x=$(echo "scale=20;1+$i/200" | bc) z=$(echo "scale=20;1/6" | bc) x2z=$(echo "scale=20;e($z*l($x))" | bc -l) y12=$(echo "scale=20;-$y*12" | bc) x2z2y12=$(echo "scale=20;e($y12*l($x2z))" | bc -l) p=$(echo "scale=3;$a*(($x2z-1))/(1-$x2z2y12)" | bc)

Print the monthly payment

echo $p exit 0

Answer 1

Arguments of a shell script are just $1, $2, $3 and so on. For example, put echo $2; echo $1 in a script.sh file, make it executable, and run it as ./script.sh one two.

In your script;

i=$1

a=$2

y=$3

and run it as ./myscript.sh 3 4 23. Now i will be 3, a will be 4 and y will be 23.

Answer 2

You've only told getopts that -y has an argument. You're also missing the "do" from the "while" command.

You also don't need to check that the number of args is 3 any more - in fact, there won't be 3 args, there will be 6. But arg counting is the wrong method to use with getopts. Instead, check that your required variables all have a value.

Try

#! /bin/sh

usage() {
    echo "Usage:"
    echo "       $0 -i rate -a amount -y period"
    exit 1
} 

i='' ; a='' ; y=''

while getopts i:a:y: name ; do
    case $name in
            i) i="$OPTARG" ;;
            a) a="$OPTARG" ;;
            y) y="$OPTARG" ;;
            *) usage ;;
    esac
done
shift $(( OPTIND - 1 ))

if [ -z "$i" ] || [ -z "$a" ] || [ -z "$y" ] ; then 
    usage
fi

# Compute the monthly payment
x=$(echo "scale=20;1+$i/200" | bc)
z=$(echo "scale=20;1/6" | bc)
x2z=$(echo "scale=20;e($z*l($x))" | bc -l)
y12=$(echo "scale=20;-$y*12" | bc)
x2z2y12=$(echo "scale=20;e($y12*l($x2z))" | bc -l)
p=$(echo "scale=3;$a*(($x2z-1))/(1-$x2z2y12)" | bc)

# Print the monthly payment
echo $p
exit 0

Answer 3

Finally I Find answer Thinks to everyone who helped

this is code:

# Use “getopts” to give options to the script
while getopts "i:a:y:" option; do
case $option in
i)
i=$OPTARG
;;
a)
a=$OPTARG
;;
y)
y=$OPTARG
;;
\?)
echo -e "\nUsage: mortgage rate amount period\n"
exit 1
;;
esac
done

# Compute the monthly payment
x=$(echo "scale=20;1+$i/200" | bc)
z=$(echo "scale=20;1/6" | bc)
x2z=$(echo "scale=20;e($z*l($x))" | bc -l)
y12=$(echo "scale=20;-$y*12" | bc)
x2z2y12=$(echo "scale=20;e($y12*l($x2z))" | bc -l)
p=$(echo "scale=3;$a*(($x2z-1))/(1-$x2z2y12)" | bc)

# Print the monthly payment
Echo “Your Monthly is $p”
exit 0