Re: How to incorporate network blocks

[Grant Taylor via users]

On 11/11/22 10:10 AM, Bill Cole wrote:

 From my bashrc...

# type cidrcon
cidrcon is a function
cidrcon ()
{
     for a in $*;
     do
         echo $a;
     done | perl -e "use Net::CIDR::Lite;  \$cidr = Net::CIDR::Lite->new(<>) ; \$_ = join 
(\"\n\",\$cidr->list) ; print \"\$_\n\";"
}

Oh ... (minimally) obfuscated Perl one liner.

N.B. My Perl is rusty.

Let's try deobfuscating and interpreting.

use Net::CIDR::Lite;

Load the Net::CIDR::Lite module.

$cidr = Net::CIDR::Lite->new(<>);

Instantiate an instance of the Net::CIDR::Lite module.

It also looks like you're reading from STDIN via "<>".  Is that correct?

I feel like that's a Perlish short cut to opening the STDIN. I have almost always used an "open" statement for such.

$_ = join ("\n",$cidr->list);

Set the unnamed variable to the output of the list output from the Net::CIDR::Lite object using new lines.

print "$_\n";

Print the unnamed variable with a trailing new line.

I /think/.

Am I close?

Obviously requires Perl and the Net::CIDR::Lite module. I do not recall why the implementation is so weird, but I've been using it for decades(!?)

The deobfuscated code doesn't seem weird to me.











--
Grant. . . .
unix || die

I suspect some of the weirdness comes from transforming it into a one liner and escaping things as necessary to pass it from shell to Perl. I guess it may be a little weird that the cidrcon() shell function takes multiple parameters and prints each of them on a line to pass into Perl. I wonder if it was easier / simpler to do -- what I call -- the rotation (from one line with multiple parameters to multiple lines with one parameter) in shell than to deal with them in Perl. Thank you for sharing Bill. -- Your message has been waiting for me to read, analyze, assimilate, and reply. ;-)

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