> perl -v

This is perl, v5.10.1 (*) built for i686-cygwin-thread-multi-64int
(with 13 registered patches, see perl -V for more detail)

Copyright 1987-2009, Larry Wall

Perl may be copied only under the terms of either the Artistic License
+ or the
GNU General Public License, which may be found in the Perl 5 source ki
+t.

Complete documentation for Perl, including FAQ lists, should be found 
+on
this system using "man perl" or "perldoc perl".  If you have access to
+ the
Internet, point your browser at http://www.perl.org/, the Perl Home Pa
+ge.

> cat tmp.pl 
#!/usr/bin/perl
sub mysub {
        die 'single word expected' if (my $name = shift) !~ /^\w+$/;
        die 'single word expected' if (my $value = shift) !~ /^\w+$/;
}
$str = "abc def";
$str =~ /(\w+)\s+(\w+)/;
mysub($1, $2);


> ./tmp.pl 
single word expected at ./tmp.pl line 4.

[download]
perlvar says "read-only and dynamically scoped" 
$<digits> ($1, $2, ...)

    Contains the subpattern from the corresponding set of capturing pa
+rentheses from the last successful pattern match, not counting patter
+ns matched in nested blocks that have been exited already. (Mnemonic:
+ like \digits.) These variables are all read-only and dynamically sco
+ped to the current BLOCK.

[download]
I'm confused a bit
have decided to post here

In reply to unexpected: inside sub($1,$2) if do // then arguments will be changed by bdimych

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.