You can use these scripts on your own system.
Source text has to be given on standard input and converted text appears on standard output.
It should be understood that reverse transliteration is an intrinsically ambiguous operation, because certain Cyrillic characters correspond to two, or even more, Latin ones. And with pasha , you are stuck altogether. Let's say, it will not always undo the transliteration by cyr-conv correct. I will be really interested in your feedback and suggestions on how to teach it better. The algorithm it uses is exceedingly simple.