问题
I have to variables and I want to find the value of one divided by the other. What commands should I use to do this?
回答1:
In the bash shell, surround arithmetic expressions with $(( ... ))
$ echo $(( 7 / 3 ))
2
Although I think you are limited to integers.
回答2:
echo 5/2 | bc -l
2.50000000000000000000
this '-l' option in 'bc' allows floating results
回答3:
Better way is to use "bc", an arbitrary precision calculator.
variable=$(echo "OPTIONS; OPERATIONS" | bc)
ex:
my_var=$(echo "scale=5; $temp_var/100 + $temp_var2" | bc)
where "scale=5" is accuracy.
man bc
comes with several usage examples.
回答4:
I still prefer using dc, which is an RPN calculator, so quick session to divide 67 by 18 with 4 digits precision would look like
>dc
4k
67
18/p
3.7222
q
>
Obviously, much more available: man dc
回答5:
You can use awk which is a utility/language designed for data extraction
e.g. for 1.2/3.4
>echo 1.2 3.4 | awk '{ print $2/$1 }'
0.352941
回答6:
In bash, if you don't need decimals in your division, you can do:
>echo $((5+6))
11
>echo $((10/2))
5
>echo $((10/3))
3
回答7:
I assume that by Linux console you mean Bash.
If X and Y are your variables, $(($X / $Y)) returns what you ask for.
回答8:
Example of integer division using bash to divide $a by $b:
echo $((a/b))
回答9:
Something else you could do using raytrace's answer. You could use the stdout of another shell call using backticks to then do some calculations. For instance I wanted to know the file size of the top 100 lines from a couple of files. The original size from wc -c is in bytes, I want to know kilobytes. Here's what I did:
echo `cat * | head -n 100 | wc -c` / 1024 | bc -l
回答10:
You should try to use:
echo "scale=4;$variablename/3"|bc
回答11:
you can also use perl -e
perl -e 'print 67/8'
回答12:
I also had the same problem. It's easy to divide integer numbers but decimal numbers are not that easy.
if you have 2 numbers like 3.14 and 2.35 and divide the numbers then,
the code will be Division=echo 3.14 / 2.35 | bc
echo "$Division"
the quotes are different. Don't be confused, it's situated just under the esc button on your keyboard.
THE ONLY DIFFERENCE IS THE | bc and also here echo works as an operator for the arithmetic calculations in stead of printing.
So, I had added echo "$Division" for printing the value. Let me know if it works for you. Thank you.
来源：https://stackoverflow.com/questions/1088098/how-do-i-divide-in-the-linux-console