在 Perl 中，如何从变电站的外部命令 append 与 output 进行正则表达式匹配？

Question

Let's say I have a list of IPs that looks like this:

10.2.3.4
10.5.3.2
10.5.3.1
...

I know about the 'e' option in regex, which does an eval against the replacement string. I just wanted to do a straight up replacement, I could do this:

s/(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})/`{$1}dig -x $1 +short`/ge;   

But, what I really want to do is append the host name to regex match like this:

10.2.3.4 website.example.com
10.5.3.2 dc01.example.com
10.5.3.1 dc02.example.com
...

Answer 1

If you all you need to do is append, you don't need a regex at all. Just do:

chomp($_ .= '  ' . qx(dig -x $_ +short)) for @list;

I'm not sure what the {$1} is for in your example, though.

Answer 2

s/(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})/$1.`{$1}dig -x $1 +short`/ge;

Answer 3

Try this, it works for me:

s/(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})/"$1 ". `dig -x $1 +short`/ge;