Basic Git Questions

Hi,

1. I generally add the files in my working directory using "git add
.". But sometimes you want to add all the files except 1 or 2 file. Is
there a shortcut way we can tell git to add all the files but exclude
a particular file.

2. Also sometime when the code is committed, I realize that I have
forgot to change or add a file. Is there a way we can we commit a file
to existing commit number with git log showing only the old git commit
number and not creating a new one for the last commit.

Cheers,
Parag