shell float number in expr

I'm trying to get a float number fro开发者_StackOverflow中文版m this :

totalmark=$(expr $sum / $subjects )

Is this correct?

bash doesn't support floats, use awk or bc/dc

eg awk

totalmark=$(awk 'BEGIN{print $sum / $subjects}')

or bc

totalmark=$(echo "scale=2;$sum/$subjects"|bc)

if you have the luxury to use different shells other than bash, try zsh or ksh

$ zsh -c 'echo $((4/1.3))'
3.0769230769230766

$ ksh -c 'echo $((4/1.3))'
3.07692307692307692

I don't think bash has floating-point capabilities. You can try:

echo "$sum/$subjects" | bc -l

Bash doesn't support floating point arithmetic. Try bc instead.

totalmark=$(echo "scale=4;$sum/$subjects"|bc)

By the way, three answers say that Bash doesn't support floating point arithmetic. While that is true, expr is an external program (/usr/bin/expr for me) and it's the one, in particular, in this case which doesn't support floats.