I would do it sequentially. Starting with your first question, I'd remove extra whitespace.

#!/usr/bin/perl -l

use strict;
use warnings;

my $str = "this is an   example";
$str =~ s/\s+/ /g;
print $str;
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I tried a bunch of different methods, but this was the most consistent, easiest way that I could find.

Update: I modified the code from String::Trim so that it only removes extra whitespace from within the string:

#!/usr/bin/perl -l

use strict;

my $str  = "This is a    start,  but not   a finished product     howe
+ver. ";
my @str = ('This is a     start,  ', 'but not      a finished product 
+   however. ');
trim($str);
trim(@str);
print $str;
print @str;

sub trim {
        my $t =~ s/\s+/ /g;
        if (defined wantarray) {
        @_ = (@_ ? @_ : $_);
        if (ref $_[0] eq 'ARRAY') {
            @_ = @{ $_[0];};
            foreach $_ (@_) { 
                s/\s+/ /g if defined $_ 
            }
            return \@_;
        }
        elsif (ref $_[0] eq 'HASH') {
            foreach my $k (keys %{$_[0];}) {
                (my $nk = $k) =~ s/\s+/ /g;
                if (defined $_[0]->{$k}) {
                    ($_[0]->{$nk} = $_[0]->{$k}) =~ s/\s+/ /g;
                }
                else {
                    $_[0]->{$nk} = undef;
                }
                delete $_[0]->{$k} unless $k eq $nk;
            }
        }
        else {
            for (@_ ? @_ : $_) { s/\s+/ /g if defined $_ }
        }
        return wantarray ? @_ : $_[0];
    }
    else {
        if (ref $_[0] eq 'ARRAY') {
            for (@{ $_[0] }) { s/\s+/ /g if defined $_ }
        }
        elsif (ref $_[0] eq 'HASH') {
            foreach my $k (keys %{ $_[0] }) {
                (my $nk = $k) =~ s/\s+/ /g;
                if (defined $_[0]->{$k}) {
                    ($_[0]->{$nk} = $_[0]->{$k}) =~ s/\s+/ /g;
                }
                else {
                    $_[0]->{$nk} = undef;
                }
                delete $_[0]->{$k} unless $k eq $nk
            }
        }
        else {
            for (@_ ? @_ : $_) { s/\s+/ /g if defined $_ }
        }
    }
}
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