You can manage and send your ussd code with ussdpad .its simple and easy to use gui program written by use python and qt4 - Shashika Layan
* Install Method (ArchLinux)
It's Available on Arch User Repository (AUR) so you can install it use yaourt
$ yaourt -S ussdpad
(1) Software that generates a customized, secure Linux distribution (Debian, ArchLinux, Kali, ...) for your Chromebook. (2) Images for download, to save you the trouble. (3) More to come...