That depends a whole lot on what you want to achieve actually. Simplisticly you could use a regex to extract runs of uppercase letters. Something like:

my $runs = $str =~ /([A-Z]+)/g;
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But one of your strings looks like it ought have digits on the end so you may want to augment that to:

my $runs = $str =~ /([A-Z]+\d*)/g;
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That finds runs of upper case characters optionally followed by digits. But that may not be the end of the variations that you need to match so you may be better with a much fussier regex. For example:

my @runs = $str =~ /".*?\\([^\\"]*)"[^"]*"[^A-Z]*((?:(?! size).)+)/g;
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Could you give us a few lines you actually intend to process, and the output you would like to see?

Using something like split, on the (stated) assumption that the field locations are fixed or that double quotes (") are present would probably break in the future.

To give some (virtually untested!) code:

#!perl

use strict;
use warnings;

my $string = "add vdisk \"\\vdisks\\type 1\\vdname\" ".
             "disk_group=\"\\d gs\\diskgrp1\" size=500";

# split on quotes

my @quotes = split(/\"/, $string);

print "\@quotes:\n\t" . join("\n\t", @quotes) ."\n";;

# @quotes should be 'add vdisk'.
#                   '\\vdisks\\type 1\\vdname',
#                   'disk_group=',
#                   '\\d gs\\diskgrp1\\',
#                   'size=500'

# split the second element on backslashes...

my @back = split(/\\/, $quotes[1]);

print "\@back:\n\t" . join("\n\t",@back)."\n";

# and popout the last element...
my $is_this_it = pop(@back);
print  $is_this_it,"\n";
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produces

vdname
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(One of the regex wizards here could probably reduce that to 1 line; I could probably reduce it to about 3, but I was deliberately verbose.)

I don't know about a single best way, but here's a pretty good way:

my @var = $line =~ /([A-Z]+)/g;
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UPDATE: no blazar and ikegami -- he wrote something along the lines of "grab the capitolized letters" BEFORE he changed his question.

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

"I capitalized for demo purposes" implies these won't always be capitalized.

Hmmm, he wrote:

give me the characters between the third \ and the ", assming you just read thru the text "add vdisk"

IIUC, a stricter translation (also taking into account the example line of text) of that sentence to a match would be

/add vdisk.*?(?:\\[^\\]*?){2}\\([[:alpha:]]+)\b/;
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