Question: So, on each branch if I do "git log" or "git lg", it will show a list of commits done.

Now, is there a way to display the latest commit on each branch when I enter "git branch -arg"? I find it a bit annoying/tedious to have to checkout each branch then check the commits using "git log".

Answer: 
`git branch -v` lists branch names and the SHA and commit message of the latest commit on each branch.

See the [git branch manual page](http://www.kernel.org/pub/software/scm/git/docs/git-branch.html).
Yes, you can add a post-checkout hook ([described here](https://stackoverflow.com/questions/1504724/a-git-hook-for-whenever-i-change-branches)).

Basically, create the `.git/hooks/post-checkout` file and put whatever git command you want to run in it, and finally make sure to make that file executable (`chmod +x .git/hooks/post-checkout` on unix-like systems, such as Mac OS, GNU/Linux, etc).

For example, if you put `git show` in that file, it will automatically show you the last commit and what changes were made whenever you switch branch.