I'm trying to extract the sum of numbers to a variable (cwr) in a file (wa_cidr) using this command:
我正在尝试使用此命令将数字总和提取到文件（wa_cidr）中的变量（cwr）：
cwr=$(grep -E "^([0-9]{1,3}\.){3}[0-9]{1,3}(\/([0-9]|[1-2][0-9]|3[0-2]))?$" /tmp/wa_cidr | awk -F '/' '`{n += 2**(32 - $NF)}` END {print n}')
However, the output is empty.
但是，输出为空。
If I change the part...
如果我改变了部分......
{n += 2**(32 - $NF)}
To...
至...
{n += (32 - $NF)}
I get a valid result written to the cwr variable.
我得到一个写入cwr变量的有效结果。
It would seem that I cannot do the power of (32 - $NF) using either 2**X or 2^X in AWK.
似乎我无法在AWK中使用2 ** X或2 ^ X来执行（32 - $ NF）的功能。
If I do it on the command line, e.g. using...
如果我在命令行上执行此操作，例如使用...
$ echo $(2**5)
There's no problem and the result is 32.
没有问题，结果是32。
I have tried many variations on the formula (parantheses etc.) but nothing seems to Work.
我已经尝试了很多公式（parantheses等）的变化，但似乎没有任何工作。
What is wrong? Can it be done in another way?
哪里不对？可以用另一种方式完成吗？
Thanks, Søren
谢谢，Søren
2 个解决方案
#1
1
If your regexp is correct then this would be the correct syntax to do what you appear to be trying to do:
如果你的正则表达式是正确的，那么这将是你正在尝试做的事情的正确语法：
cwr=$(awk -F'/' '/^([0-9]{1,3}\.){3}[0-9]{1,3}(\/([0-9]|[1-2][0-9]|3[0-2]))?$/{n += 2^(32 - $NF)} END {print n+0}' /tmp/wa_cidr)
#2
1
Hmmm, it would appear that I was on to something, when I mentioned that something was limited in the DD-WRT Shell.
嗯，当我提到DD-WRT Shell中的某些内容有限时，看起来我还有所作为。
According to this website, https://rosettacode.org/wiki/Exponentiation_operator#awk, the "traditional awk implementations do not provide an exponent operator, so we define a function to calculate the exponent".
根据这个网站，https：//rosettacode.org/wiki/Exponentiation_operator#awk，“传统的awk实现不提供指数运算符，所以我们定义了一个函数来计算指数”。
So for the code to Work it needs to look something like this:
因此，要使代码工作，它需要看起来像这样：
cwr=$(grep -E "^([0-9]{1,3}\.){3}[0-9]{1,3}(\/([0-9]|[1-2][0-9]|3[0-2]))?$" /tmp/wa_cidr | awk -F '/' 'function pow(x,n){r=1;for(i=0;i<n;i++)r=r*x;return r}{c += pow(2,(32-$NF))} END {print c}')
Which gives the correct value of 3996.
其中给出了正确的3996值。
Thank you all for inputs!
谢谢大家的投入！
/Søren
/索伦
#1
1
If your regexp is correct then this would be the correct syntax to do what you appear to be trying to do:
如果你的正则表达式是正确的，那么这将是你正在尝试做的事情的正确语法：
cwr=$(awk -F'/' '/^([0-9]{1,3}\.){3}[0-9]{1,3}(\/([0-9]|[1-2][0-9]|3[0-2]))?$/{n += 2^(32 - $NF)} END {print n+0}' /tmp/wa_cidr)
#2
1
Hmmm, it would appear that I was on to something, when I mentioned that something was limited in the DD-WRT Shell.
嗯，当我提到DD-WRT Shell中的某些内容有限时，看起来我还有所作为。
According to this website, https://rosettacode.org/wiki/Exponentiation_operator#awk, the "traditional awk implementations do not provide an exponent operator, so we define a function to calculate the exponent".
根据这个网站，https：//rosettacode.org/wiki/Exponentiation_operator#awk，“传统的awk实现不提供指数运算符，所以我们定义了一个函数来计算指数”。
So for the code to Work it needs to look something like this:
因此，要使代码工作，它需要看起来像这样：
cwr=$(grep -E "^([0-9]{1,3}\.){3}[0-9]{1,3}(\/([0-9]|[1-2][0-9]|3[0-2]))?$" /tmp/wa_cidr | awk -F '/' 'function pow(x,n){r=1;for(i=0;i<n;i++)r=r*x;return r}{c += pow(2,(32-$NF))} END {print c}')
Which gives the correct value of 3996.
其中给出了正确的3996值。
Thank you all for inputs!
谢谢大家的投入！
/Søren
/索伦