The section of the book:
http://git-scm.com/book/en/Git-Basics-Recording-Changes-to-the-Repository#Staging-Modified-Files
says that if I change file A, run 'git add A' and then change file A again, run 'git commit' on this file, only previously staged changes will be committed. To commit unstaged changes - add file again and then commit.
After some testing, however it turns out that git commits all changes of the file A, even those that were made after the file had been staged initially.
Can anyone shed some light on this matter? Thanks.
EDIT: I am not using -a option It looks like if I specify the file explicitly for "git commit A" (I am not using -a option), it commits unstaged changes as well. Committing without file "git commit" asks to enter a commit message and then behaves as described in the book.