Is it really possible with rails?

Yes this is all possible. See comments below on each item.

Hi everyone!

I've been developing dinamic websites with Php for a long time. I'm
really new to Rails.

I' ve thinking of a project for a long while, and technicaly speaking,
is possible with php. In fact, i've already got it started with php.

I'm wondering wether RoR could do the trick easier and faster. So i'm
gonna name a list of features I need for my Project and I hope you, that
already use RoR and have more experience, could tell me if is possible
to implement them or not.

My project needs:

> User login and sessions.

You can roll your own ala "Agile Web Development with Rails", or use
one of several plugins/generators.

> Several automatic e-mail sending proccesses

If these are stimulated by user actions no problem. If they are
scheduled or periodic you probably want to initiate them using
BackgrounDrb

> Capturing users IP

You have access to the request header, I presume it is in there if
anywhere.

> File uploading, with ext,size and mimetype restrinctions.

There are several file upload plugins and lots of web based material
on this.

> System functions calls and retrieving it's results. (Output and
result[0,1])
        Ex: Sort like exec() in Php or system() en C.

Ruby can call C code so this should not be an issue. It might be
possible with the standard libraries, but I am not sure on that. If
you are trying to host this on a shared host you may run into issues
with them, but it is technically not an issue.

> Search engine for contents

There are several plugins that support search. Solr and ferret are
the most commonly mentioned.

Neighter exec nor system call system functions. They running new
processes.
In ruby it is done by `command` (somewhere on this group it was mentioned
on Sunday).

Regards