Why don't you just use Firefox's internal updater, and it will automatically update your Firefox to the latest version when it becomes available? (I'm assuming this is for windows, not your Linux system, as you posted about the windows registry).

Updating Firefox has more information about how to update Firefox.

Unless I'm terribly misunderstanding your question ;)

The problem is when the user has a versión lower than 3.6 and trust me, I have a lot of those, but in the version 4.0 + there is a way I can update from the command line?

Pd yes, is windows

You can use Firefox 3.6's and belows auto update to update to Firefox 10 as well. you just have to either run updates several times until it gets to 10, or, just download and install the exe for 10. even installing Firefox 10 or Firefox 10 won't hurt anything so long as it is the same or later version.

I Am not aware of a way to update using CLI, but https://wiki.mozilla.org/Deployment:Deploying_Firefox might help you.

well, I can't update manually, thats why I have a script, but I want to save the bandwith if the user already has version 10.0.2. thks anyway

I think I solved, all I have to do is this:

//here I download the entire page

wget.exe http://www.mozilla.org/en-US/firefox/all.html -O index

//here I search for the word curVersion and set a variable with the result, which is "10.0.2"

for /f "tokens=3 delims= " %%A IN ('type index ^| FIND /I "curVersion" ' ) do set latestversion=%%A

//here I just make sure I get a number

echo "%latestversion%" pause

Later I check it against the registry and voila! I hope this can help other admins who have the same problem.

Regards.