use strict;
my $str = '$plugins.official.random_hsv_color_as_rgb.RandomHsvColorAsRgb';
my $regex = qr/\$plugins\.(\w+)\.(.+)/p;
my $subst = 'plugins.\\1.process_conditions.variabilities.\\2';
my $result = $str =~ s/$regex/$subst/r;
print "The result of the substitution is' $result\n";
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html