Help on bug reporting for newbies

[Dominique Meeùs]

Bug reporting is very common for hackers, I suppose. I am not a hacker 
but I like GNU, I like Ubuntu and I suppose I do help improving things 
if I report a bug. But what is exactly a bug? How do you report a bug 
efficiently? What is the "etiquette" of bug reporting? (The first bug I 
reported I felt was serious, not only for me but for everybody. I feared 
it would not be taken seriously enough and I was a bit aggressive in 
stressing its importance. The maintainer answered that it was no use to 
upset the very people who would help me!)

I would be glad that somebody points to me a resource on these matters. 
I would find much better that a link to some help of the kind would 
appear visibly on most of the pages of the Launchpad website. (I did 
search on Launchpad but didn't find any.)

-- 
Dominique.