Can I do basic maths in Bash?

Question

I was wondering, is it possible to do simple maths in bash? I'm thinking something like, =25-5 would print out 20 or something.

Can this be done easily?

Thank you

Answer 1

Just type "bc" no quote into the terminal. Then type all the math stuff in after that.

Answer 2

If we are really talking about Bash, not Bourne Shell (sh) or other shells, it's easy.

Bash can compute basic expressions with $((expression)) and here's an example on how you might like to use it:

 a=3
 b=4
 c=$((7*a+b))
 echo $c

or for interactive use, just

 echo $((7*3+4))

Answer 3

There are a number of command-line utilities for doing simple calculations:

$ expr 100 \* 4
400

$ echo '100 * 4' | bc
400

to name just two of them. Be careful doing multiplication as if you don't escape your * the shell may try and interpret it as a wildcard.

Answer 4

Well your question is answered, but consider this:

Most of the linux distros have python preinstalled, so why not use it?

Just type

python

in the terminal and then do all the arithmetics you want, like

2+2

Will output 4 :)

Answer 5

Another is AWK:

awk 'BEGIN {4 + 3 / 12}'

Answer 6

Or Ruby. :)

Although it may not come pre-installed, it is pretty quick.

Type irb, then 2+2.