I am looking for a calculator which can do calculations in the terminal itself, without any other extra prefixes and suffixes.
For example: If I typed something like 10000-9000 in the terminal, the answer should come out as 1000.
Once again I am saying, I just need a quick calculator in the terminal, without any characters added. I know if I switch to Python, it can do that, but I don't want it in such a way.
25 Answers
You can use calc. Is not installed by default, but you can install it quickly using the following command:
sudo apt-get install apcalc
After you have installed, you can do any calculation do you wish:
$ calc 5+2
7
$ calc 5-2
3
$ calc 5*2
10
$ calc 5/2
2.5
$ calc 5^2
25
$ calc 'sqrt(2)'
1.4142135623730950488
$ calc 'sin(2)'
0.9092974268256816954
$ calc 'cos(2)'
-0.416146836547142387
$ calc 'log(2)'
~0.30102999566398119521
$ calc 'sqrt(sin(cos(log(2))))^2'
~0.81633199125847958126
$ # and so on...
For more information , view its man-page
You can do simple integer arithmetic natively in bash using the ((...)) syntax, e.g.
$ echo $((10000-9000))
1000
There is also the bc calculator, which can accept arithmetic expressions on standard input
$ echo "10000-9000" | bc
1000
The bc program can do floating point arithmetic as well
$ echo "scale = 3; 0.1-0.09" | bc
.01
Bash Arithmetic
Another possible solution is to add a simple function for Bash's built-in arithmetic. Put this in your .bashrc file to try it out:
=() {
echo "$(($@))"
}
So now, you don't even need $((...)) anymore, just = which seems natural enough.
Replacement
Another thing if you want to be even faster: you can make it replace p with + and x with *. This will work for that:
=() {
local IFS=' '
local calc="${*//p/+}"
calc="${calc//x/*}"
echo "$(($calc))"
}
= 5 x 5 # Returns 25
= 50p25 # Returns 75
Now you don't even need Shift anymore, the only thing is = in front of arithmetic.
Hexadecimal output
Output can be displayed in both decimal and hexadecimal, if so desired. (Note: using x substitution will conflict with the 0x... hex syntax)
=() {
local answer="$(($@))"
printf '%d (%#x)\n' "$answer" "$answer"
}
Example:
$ = 16 + 0x10
272 (0x110)
$ = 16**3 + 16**4
69632 (0x11000)
