Calculating rounded percentage in Shell Script without using "bc"

Question

I'm trying to calculate percentage of certain items in Shell Script. I would like to round off the value, that is, if the result is 59.5, I should expect 60 and not 59.

item=30
total=70
percent=$((100*$item/$total))

echo $percent

This gives 42.

But actually, the result is 42.8 and I would to round it off to 43. "bc" does the trick, is there a way without using "bc" ?

I'm not authorized to install any new packages. "dc" and "bc" are not present in my system. It should be purely Shell, cannot use perl or python scripts either

Answer 1

Use AWK (no bash-isms):

item=30
total=70
percent=$(awk "BEGIN { pc=100*${item}/${total}; i=int(pc); print (pc-i<0.5)?i:i+1 }")

echo $percent
43