$str =~s/.*(John).*/$1/;

##</code><code>##

$str =~s{.* / | \. .*}{}gx;

##</code><code>##

$str =~s{ (?: [^/]* / ){5} ( \w+ ) .* }{$1}x;

##</code><code>##

print $str =~ /(John)/;
print $str =~ m{ .* / (.+) \. }x;
print $str =~ m{ (?: [^/]* / ){5} ( \w+ ) }x;

##</code><code>##

my $s = 'John';
print $s if -1 != index $str, $s;