When written in Hebrew letters, the abbreviation stands for בסיעתא דשמיא meaning, "With G-d's help".
If you have seen how cryptic UNIX commands are, believe me ... you will need loads of help from G-d to understand what some of these commands do, and how to use each commandscommand umpteen different options. The UNIX manual is practically useless for a novice. And, I've spoken to people from Berkley who were involved with BSD about the BSD / UNIX language. Let's say that after talking to them, I don't know who needs more help - they or me!
In short, if you're using BSD, G-d help you!