I am working on a git repository which contains huge number of files changed b/w one commit to another, how to extract the number of files changes b/w commits.
git whatchanged tool shows you a summary of files that were modified. By itself it lists all commits, but you can also limit it to just the recent n commits:
git whatchanged -1
To count files:
git whatchanged -1 --format=oneline | wc -l
git help whatchanged for details.