blocks|key|1511225|text|在bash+shell中，使用$((+...+))将算术表达式括起来|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1511226|$+echo+$((+7+/+3+))
2|code-block|syntax|javascript|1511227|虽然我认为你被限制为整数。|1511228|entityMap^0|F|A|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@]|D|@]|E|$]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

In the bash shell, surround arithmetic expressions with <code>$(( ... ))</code> 

<pre><code>$ echo $(( 7 / 3 ))
2
</code></pre>

Although I think you are limited to integers.

blocks|key|1296818|text|echo+5/2+%7C+bc+-l|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1296819|2.50000000000000000000|unstyled|1296820|'bc‘中的'-l’选项允许浮点结果|1296821|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|F|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>echo 5/2 | bc -l
</code></pre>

2.50000000000000000000

this '-l' option in 'bc' allows floating results

blocks|key|1296778|text|更好的方法是使用"bc"，一个任意精度的计算器。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1296779|variable=$(echo+"OPTIONS;+OPERATIONS"+%7C+bc)|code-block|syntax|javascript|1296780|例如：|1296781|my_var=$(echo+"scale=5;+$temp_var/100+%2B+$temp_var2"+%7C+bc)|1296782|其中"scale=5“表示准确度。|1296783|man+bc+|1296784|附带了几个使用示例。|1296785|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|W|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|Y|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

Better way is to use "bc", an arbitrary precision calculator.

<pre><code>variable=$(echo "OPTIONS; OPERATIONS" | bc)
</code></pre>

ex: 

<pre><code>my_var=$(echo "scale=5; $temp_var/100 + $temp_var2" | bc)
</code></pre>

where "scale=5" is accuracy.

<pre><code>man bc 
</code></pre>

comes with several usage examples.

blocks|key|1296916|text|您可以使用awk，这是一种为数据提取而设计的实用程序/语言|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1296917|例如，对于1.2/3.4|1296918|>echo+1.2+3.4+%7C+awk+'{+print+$2/$1+}'
0.352941|code-block|syntax|javascript|1296919|entityMap|0|LINK|mutability|MUTABLE|url|http://en.wikipedia.org/wiki/AWK^0|5|3|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|6|7|W|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|X|8|@]|9|@]|C|$I|J]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

You can use <a href="http://en.wikipedia.org/wiki/AWK">awk</a> which is a utility/language designed for data extraction

e.g. for 1.2/3.4

<pre><code>&gt;echo 1.2 3.4 | awk '{ print $2/$1 }'
0.352941
</code></pre>

blocks|key|1511346|text|在bash中，如果您的除法中不需要小数，您可以这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1511347|>echo+$((5%2B6))
11
>echo+$((10/2))
5
>echo+$((10/3))
3|code-block|syntax|javascript|1511348|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

In bash, if you don't need decimals in your division, you can do:

<pre><code>&gt;echo $((5+6))
11
&gt;echo $((10/2))
5
&gt;echo $((10/3))
3
</code></pre>

blocks|key|1296681|text|使用bash将$a除以$b的整数除法示例：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1296682|echo+$((a/b))|code-block|syntax|javascript|1296683|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Example of integer division using bash to divide $a by $b:

<pre><code>echo $((a/b))
</code></pre>

blocks|key|1511466|text|你可以使用raytrace的答案来做一些其他的事情。您可以使用另一个shell调用的stdout来执行一些计算。例如，我想知道几个文件中前100行的文件大小。wc+-c的原始大小是以字节为单位的，我想知道千字节。下面是我所做的：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1511467|echo+`cat+*+%7C+head+-n+100+%7C+wc+-c`+/+1024+%7C+bc+-l|code-block|syntax|javascript|1511468|entityMap^0|27|5|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

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 <code>wc -c</code> is in bytes, I want to know kilobytes. Here's what I did:

<pre><code>echo `cat * | head -n 100 | wc -c` / 1024 | bc -l
</code></pre>

blocks|key|1296945|text|您应该尝试使用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1296946|echo+"scale=4;$variablename/3"%7Cbc|code-block|syntax|javascript|1296947|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You should try to use:

<pre><code>echo "scale=4;$variablename/3"|bc
</code></pre>

blocks|key|1511600|text|您也可以使用perl+-e。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1511601|perl+-e+'print+67/8'|code-block|syntax|javascript|1511602|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

you can also use perl -e

<pre><code>perl -e 'print 67/8'
</code></pre>

blocks|key|1511673|text|我也有同样的问题。整数的除法很容易，但小数就没那么容易了。如果你有像3.14和2.35这样的两个数字，然后将它们相除，代码将是Division=echo+3.14+/+2.35+%7C+bc+echo+"$Division“，引号是不同的。别搞混了，它就在你键盘上的esc键下面。唯一的区别是%7C+bc，这里echo也是作为算术计算的运算符，而不是打印。因此，我添加了echo+"$Division“来打印值。如果对你有效，请让我知道。谢谢。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1511674|entityMap^0|20|L|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

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=<code>echo 3.14 / 2.35 | bc</code>
 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.

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?

How do I divide in the Linux console?

我必须计算变量，我想找出一个变量除以另一个变量的值。我应该使用什么命令来做这件事？

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