Module development and code questions

Hey guys,

I'm try to do a module that saves just one specific file with a upload form, like an attachment, with a "browser" button and an input text. But i don't understand how can i do the files should be save! how can i save the files from a computer (for example?) Is there a specific module that can i have grounds? or did you know a way? please guys, help me!

Thanks about the attention!

Why does upload.modules save in .txt?

for exemple, whe i try attach some file with upload.module it saves the file in .txt.
I'm trying attach a *.mtf file and i set in settings the file extension... but when i hit down the attach button it come back with "name.mtf.txt"

why?? may anyone help me? pleease!!

Greetings,
When new versions of category.module (or other modules) are updated is it just a matter of overwriting the files in the modules folder? I've read a couple of threads on 4.7 that the database will not be affected once the official version is released.
Mil gracias,
lsabug

I'm saving and retrieving custom fields with the user information, but not using the profile module. So I've written the hook_user() function in my module and I can enter these new fields at registration of a new user and edit the account. I wrote my own load and save functions and everything loads and saves. Life is great.

One thing I miss in Drupal is a staging/testing function, to check new versions, modules, templates etc before putting it on the live server. So I'll try to write a module for this.

[First question: is someone already working on this?]

I'll give a outline of my plans here, hoping to get weak parts critizised and some questions answered.

Functionality of the module will be inspired by the method described in http://drupal.org/creating-drupal-test-sites

I want to be able to not only upload one image but multiple images with the same post.