Git how to take diff

1)
Find log
#git log -n 9

2)
Take diff between two commits
# git diff prev-commit-id..next-commit-id > ~/Desktop/mychanges.diff

#git diff 7a51bc7ddd57b39fa3cd..1f81be4c220dbc8cc > ~/Desktop/mychanges.diff

3)
How to see changes in a commit
$git diff 14bbce77a91e666f779ae9feb98ea30aa6249564^!

$git diff 14bbce77a91e666f779ae9feb98ea30aa6249564^! filename.py

4)
Git How to search in diff and commit message and find commit id

http://fosshelp.blogspot.in/2015/06/git-how-to-search-in-diff-and-commit.html