Shell Programming and Scripting

I would like to add 4.7 and 1.2. However I am unable to do this with expr.
Any simple ideas (even using something other than expr)?

Example:
me> expr 4 + 1
5

me> expr 4.7 + 1.2
expr: 0402-046 A specified operator requires numeric parameters.

awk '{BEGIN print 4.7 + 1.2}'

or might try bc - never used it but

NAME
bc - arbitrary-precision arithmetic language

Might want to try a man on bc

sorry - that should be

awk 'BEGIN{.....

If you are using ksh93, it has floating-point arithmetic built in:

Code:

echo $(( 4.1 + 1.2 ))

If not, I recommend awk. I use this shell function:

Code:

calc()
{
  awk 'BEGIN {print '"$*"'; exit}'
}

Thank for the replies! Both examples look good I just have not tried them yet. I will let you know once I do. Would there be something similar used to multiply, divide, and subtract? If so could you give an example?

Use * , / or - instead of + in the above code

Thanks for the replies guys keep them coming.

Ok I guess I am not using ksh93 since echo returned an error. I was able to use the awk function to subtract, add, multiply. However when I try to get a percentage with only two decimal places it doesn't seem to work that well. Any suggestions for this?

me> cat test.sh
#!/usr/bin/sh

calc()
{
awk 'BEGIN {print '"$*"'; exit}'
}

calc "1188 %.2f 1454.07"
calc "1188 / 1454.07 * 100"

me> test.sh
0.21454.07
81.7017