note the commma and semi collens here
for ((i=0,j=10;i<=j;i++,j--))
do
echo "i=$i"
echo "j=$j"
done
i=0
j=10
i=1
j=9
i=2
j=8
i=3
j=7
i=4
j=6
i=5
j=5
# something complex
somethong omp
$id1=120
$id2=170
##
for (( a=$id1, b=$id2; a < 59 + $id1 && b < 61 + $id2; a=$((a+10)), b=$((b+10)) ));
do
echo "d1 = $a d2 = $b "
done
####