Question

How to write a bash shell script that prints a hollow box after user enters number of lines, ie "bash hbox 4" , prints:

****
*   *
*   *
****

My code doesnt work. i need it to take in the argument from the command line: ./hbox 4 "*"

echo "Enter number of rows"
read sz

clear

for (( x = 1; x <= $sz; x++ )); do
    for (( y = 1; y <= $sz; y++ )); do
        if [ "$x" == 1 ] || [ "$x" == "$sz" ] || [ "$y" == 1 ] || [ "$y" == "$sz" ]
         then
            echo "* "
        else
            echo " "
        fi
     done
     echo -ne ""
done

Answer 1

WIthout Command Line Arguments:

echo "Enter number of rows"
read sz

clear

echo "$sz"

for (( x = 1; x <= $sz; x++ )); do
for (( y = 1; y <= $sz; y++ )); do
if [ "$x" == 1 ] || [ "$x" == "$sz" ] || [ "$y" == 1 ] || [ "$y" == "$sz" ]
then
printf "* "
else
printf " "
fi
done
echo -n ""
done

Here is the screenshot below:

BashScript with command line arguments:

First argument is contained in $1 and second argument in $2

for (( x = 1; x <= $1; x++ )); do
for (( y = 1; y <= $1; y++ )); do
if [ "$x" == 1 ] || [ "$x" == "$1" ] || [ "$y" == 1 ] || [ "$y" == "$1" ]
then
printf "$2 "
else
printf " "
fi
done
echo -n ""
done