unix shell scripting subtraction for floating point numbers

Question

#!/bin/ksh

a=8.3
b=10.20
diff=`expr $b - $a`
echo "$diff"

its giving

expr: 0402-046 A specified operator requires numeric parameters. error i want output as 1.9

you could use bc instead : echo $b-$a | bc. On the command line expr 3.2 - 2 gives the same result. It seems that expr can't take float: see unix.stackexchange.com/questions/165165/… — fredtantini
– fredtantini, Commented Dec 9, 2016 at 11:58
@Giri: You can provide feedback on the provided answer and accept it ( a small tick mark on left of the answer) to mark the post resolved. — Inian
– Inian, Commented Dec 12, 2016 at 5:54
As per the remarks added by a helpful person to your later question here, we do expect you to interact with people who assist you. I have upvoted the post below, and downvoted your post. — halfer
– halfer, Commented Dec 23, 2016 at 22:55

Inian · Accepted Answer · 2016-12-09 12:02:44Z

1

You don't need bc for this, use the native arithmetic operators in ksh

#!/bin/ksh

a=8.3
b=10.20
printf "%.2f\n" "$((b - a))"

outputs

$ ksh script.ksh
1.90

answered Dec 9, 2016 at 12:02

Inian

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