The implementation (a perl script) is not a one liner, but the execution (calling the perl script) is.

If the OP insists, (s)he could make it a one-liner:

perl -MHTTP::Daemon -E '$d=HTTP::Daemon->new(LocalPort=>$ARGV[0]||8000
+);say$d->url;while(my$c=$d->accept){while(my$r=$c->get_request){$c->s
+end_file_response(".",$r->url->path)}}'
[download]

Yes, this is hard to read, hard to remember, and generally a stupid idea. (And yes, I'm kind of violating my own rule.) The clean way is to use a script.

Also, writing a module optimized for using in a one-liner isn't that hard:

package HTTP::here;

use strict;
use warnings
use Exporter qw( import );
use Whatever::Webserver::you::like;

our @EXPORT=qw( serve );

sub serve
{
    my $port=shift;
    $port||=8080;
    Whatever::Webserver::you::like->new(port => $port)->run();
}

1;
[download]

Using it is as easy:

For a non-default port:

Alexander