Is this a valid robots.txt file?

[HomeRun]

User-agent: *
Disallow:


Sitemap: http://www.mysite.com/sitemap_index.xml.gz

Will it allow all crawlers to every part of mysite?

[hans]

here you find all you need about robots.txt
http://www.robotstxt.org/
read carefully !!

your "Disallow:" has no path - hence it would be WRONG code anyway most likely
and if interpreted wrongly by some bots it may do just the opposite of what you want
disallow ALL

[HomeRun]

So can I remove the disallow line and also the user agent line if I don't want to block any bots for now?

or maybe just the disallow line


Edit:
here they said no path will allow all bots to my site http://www.robotstxt.org/robotstxt.html

To allow all robots complete access
User-agent: *
Disallow:

then


To exclude all robots from the entire server
User-agent: *
Disallow: /

[hans]

yes you may have an empty robots.txt
but keep in mind that there might be folder you never want bots to be in - like entire
/cgi-bin
and
any administrative folders

[anilwebmaster]

Thks for you answers.....

I had question .... whr to insert this file... and whr to show in the source code..?

[hans]

robots.txt
always is in domain root /
there is no need to link to it
search engines always search for robots.txt at
yourdomain.com/robots.txt
by default

[manish.chauhan]

If you want to allow all bots to crawl your all website, then there is no need to add robots.txt file..