#!/usr/bin/perl --
print $_="barfoo bazfoo foofoo barfoo\n";
$snum = s/((?<!bar)foo)/{\U$1}/g;
print "$snum $_";
print '#' x 5, "\n";

print $_="barfoo bazfoo foofoo barfoo\n";
$snum = s/((?<!bar)\S{3,})/{\U$1}/g;
print "$snum $_";
print '#' x 5, "\n";

print $_="barfoo bazfoo foofoo barfoo\n";
$snum = s/((?<!bar)(?!bar)\S{3,})/{\U$1}/g; 
print "$snum $_";
print '#' x 5, "\n";

print $_="barfoo bazfoo foofoo barfoo\n";
$snum = s/\b((?<!bar)(?!bar)\S{3,})/{\U$1}/g; 
print "$snum $_";
print '#' x 5, "\n";
__END__