We use --since flag in order to show the commit logs of today:

$ git log --since="yesterday"
# or
$ git log --since="midnight"

This flag is very humanized, e.g:

$ git log --since="2 weeks ago"
$ git log --since="4am"

For more info: git-scm

Default Log

My default git log command is:

$ git log --oneline --decorate --graph --all

So I can use it with --since flag:

$ git log --oneline --decorate --graph --all --since="yesterday"

Alias

An alias would be:

alias gloga='git log --oneline --decorate --graph --all'
alias glogay='git log --oneline --decorate --graph --all --since="yesterday"'

All done!