array=( item1 item2 item3)
for name in ${array[@]}; do
    echo current/total
    ... some other codes
done

1/3
2/3
3/3

#!/bin/bash

array=( item1 item2 item3 )
for index in ${!array[@]}; do
    echo $index/${#array[@]}
done

0/3
1/3
2/3

#!/bin/bash

array=( item1 item2 item3 )
for index in ${!array[@]}; do
    echo $((index+1))/${#array[@]} = "${array[index]}"
done

1/3 = item1
2/3 = item2
3/3 = item3

dim array(0, abs(m-n));
step=sign(m-n);
if n > m then
    base=m
else
    base=n;
fi