Question

What I am trying to do is given a string like :

"hello GigabitEthernet1/13 mplampla"

to extract the interface, for example:

"GigabitEthernet1/13"

and to extract the first 2 characters and then the interface number, for example:

"Gi1/13"

What I am doing wrong ?

#!/usr/bin/perl     -w

use     strict ;
use     warnings ;

my $string = "hello GigabitEthernet1/13 mplampla" ;
$string =~ /(^[a-z]{2}*[0-9]\/*[0-9]*\/*[0-9]*)/ ;
print $string."\n" ;

PS. the interface number can be like “Po4“, “TenGigabitEthernet2/0/0.13“, etc.

Answer 1

One way:

use     strict ;
use     warnings ;

my $string = "hello GigabitEthernet1/13 mplampla" ;
my @result = $string =~ /\s(\w{2})(?:\D*)(\d+\S*)/;
{
    local $" = qq[];
    print qq[@result\n];
}

The regex:

\s                        # A space character.
(\w{2})                   # Two alphabetic characters. Save as group 1.
(?:\D*)                   # Any no-numeric characters. No save them.
(\d+\S*)                  # From first digit found until a space. Save as group 2.

For printing:

$"                  # It is the separator for array elements. It is set to a blank.
@result             # It is an array with grouped elements of the regular expression.