what will be the echo output in this scenario
 

cmd ()
{
xyz=(abc def ghi jkl mno)
echo ${xyz[$2]}
}

I am sending some numbers from a function
cmd 12 59 30 25

I am bit confused what output did the echo would throw? I am new to shell scripting. I am sorry if this question is not valid.

The echo won't show anything!
xyz will be an array where xyz[0]='abc' , xyz[1]='def', xyz[2]='ghi' .....etc

by calling the function with arguements 12, 59, 30 and 25, you are saying that $1=12, $2=59, $3=30 and $4=25

You then try to echo the 60th entry in the xyz array ( or xyz[59] ) which it doesn't have so there is nothing to display.

if you called the cmd function with cmd 2 1 3 0 it would have shown xyz[1] or "def"

I hope this is clear.

Why don't you just run the script and see what it does?

Also you can put set -x at the top of your code to have the shell show you what it is doing.