Bash, arithmetic expression + bc

Question

I have small problem with use bc command in unix. I have two varaibles: variable1, variable2. The arithmetic expression looks like:

res=$$((($variable1*10)/$variable2)

I would like to round the result from two divided numbers. I think, the best solution will be using bc -l command + scale=X, but doesn't work.

res=$$(((echo "scale=2; $variable1*10)/$variable2" | bc -l)

I would like to get more exact result. Now, f.e., I have:

res = 10

But should be

res = 9.23

"doesn't work" is *not* a very good problem report. You should be specifying what you want it to do and what it actually does (in some detail). — paxdiablo, Aug 02 '15 at 08:26
True, was changed some information. I would like to get more precise result. — profiler, Aug 02 '15 at 08:40

score 2 · Answer 1 · answered Aug 02 '15 at 08:47

2

What you currently have won't work simply because the parentheses in the bc expression are unbalanced. In addition, you appear to have way more $, ( and ) characters in there than you need.

Without those flaws, it works fine:

pax> num=923
pax> den=1000
pax> res=$(echo "scale=2; $num * 10 / $den" | bc -l)
pax> echo $res
9.23

answered Aug 02 '15 at 08:47

paxdiablo

854,327
234
1,573
1,953

Indeed, my problem was with to have to much signs $,(.). It works perfectly now. – profiler Aug 02 '15 at 09:58

Bash, arithmetic expression + bc

1 Answers1