Extract data from string by perl

You don't have to use a regex, you can use a hash for that.

use strict;
use warnings;
use Data::Dumper;

my $str = '-test aaaa   -machine  bbb  -from ccc';
my %field = split ' ', $str;
print Dumper(\%field);

The output:

$VAR1 = {
          '-from' => 'ccc',
          '-machine' => 'bbb',
          '-test' => 'aaaa'
        };

No matter what the order is, the split returns an array of pairs (in the shape [word1, word2, word3, word4, word5, word6] and word1, word3, word5 will be -field_name) that when assigned to a hash, creates it in the way that now, if you want to get the string after -test for example, you just access it by typing $field{"-test"} and do whatever you want with it.

EDIT: It doesn't even matter how many spaces you have in between the words or what characters are in the words. It works the same way for all cases as long as you keep it in the format -some_field something -another_field another_thing ...

I'm going to answer the question that (I think) underlies your question - not the question that you asked.

It looks to me like you are parsing command-line options. So use a command-line option parser, rather than reinventing that for yourself. Getopt::Long is part of the standard Perl distribution.

#!/usr/bin/perl

use strict;
use warnings;
# We use modern Perl (here, specifically, say())
use 5.010;

use Getopt::Long 'GetOptionsFromString';
use Data::Dumper;

my %options;

my $str = '-test aa_aa -machine aab-baa-aba -from ccc';
GetOptionsFromString($str, \%options, 'test=s', 'machine=s', 'from=s');

say Dumper \%options;

Normally, you'd use the function GetOptions() as you're parsing the command-line options that are available in @ARGV. I'm not sure how the options ended up in your string, but there's a useful GetOptionsFromString() function for this situation.

Update: To explain why your code didn't work.

$str = "-test aa_aa     -machine  aab-baa-aba  -from ccc";
$str =~ /-test\s*(.*)\s*/;

You're capturing what matches (.*). But .* is greedy. That is, it matches as much data as it can. And, in this case, that means it matches until the end of the line. There are (at least!) a couple of ways to fix this.

1/ Make the match non-greedy by adding ?.

$str =~ /-test\s*(.*?)\s*/;

2/ Be more explicit about what you're looking for - in this case non-whitespace characters.

$str =~ /-test\s*(\S*)\s*/;

This should do the trick

$str = "-test aa_aa     -machine  aab-baa-aba  -from ccc";
($test,$machine,$from) = $str =~ /\-test(.+)\-machine(.+)\-from(.+)/;

print "Test: $test, Machine: $machine, From: $from";