Let's say I'm running multiple instances of process `w1` (from source code `while1.c`) in the background (`while1.c` contains an infinite while loop):

    gcc while1.c -o w1
    ./w1&
    ./w1&
    ./w1&
    ./w1&
    
Now I want to get the PID of every instance. For that, I am doing this:

    var=$(/bin/ps r -o pid,cmd|grep "w1"| grep -v "grep"|awk '{print $1}')

That will store the PIDs of all instances of `w1` in `$var`.  
So, if I do:

    echo $var

It will print out the PIDs of all instances of `w1`.

But I want to access individual PIDs, i.e. something like:

    echo ${var[0]}
    echo ${var[1]}

And so on (something like arrays). How can I do that?

PS: `echo ${var[0]}` is printing all PIDs while `echo ${var[1]}` or `echo ${var[2]}` and so on, is printing nothing (i.e. blank lines of output).