robots.txt syntax question

Block access to specific file

[bcolflesh]

I want to Disallow a specific file in a subdirectory beneath root - different sites I've looked at suggest:

Disallow: myfile.html

Disallow: /myfile.html

Disallow: /subdirectory/myfile.html

Which one is correct to keep obedient spiders away from the file?

[Romeo]

... you should specify the path under document root including that subdirectory, so your 3rd Disallow: is the correct one.

You may look at
[robotstxt.org...]
for further details.

Regards,
R.