$ git add .   # All files in CWD
$ git add src # All files in src/

$ git add -- '**.py'     # All python files recursively in CWD
$ git add -- 'src/**.js' # All JavaScript files recursively in `src/`

$ git add -- ':/**.js' # Matches from top-level of repo
$ git add -- ':/**.js :/!webpack.config.js' # ! will exclude paths

$ git show e7e83086cac4f105277f34599bfd83cb9e4d5e83 # sha-1 hash
$ git show e7e8             # subset of sha-1 - must be unambigous
$ git show feature-branch   # tip of a branch
$ git show HEAD             # your current branch
$ git show feature-branch^  # parent of a commit
$ git show master^2         # second parent (for merge commits)
$ git show HEAD~            # first ancestor
$ git show HEAD~2           # second ancestor (parent of parent)

$ git log master..feature  # commits in feature and not master
$ git log feature..master  # commits in master and not feature
$ git log master...feature # commits in master or feature, not both

$ git log

Show a list of commits in reverse chronological order. Includes basic information such as author, date, and message.

$ git log -- "file.txt"

The log can be limited by pathspec as well

$ git log --patch
$ git log -p

Includes a patch history in the log. Useful for seeing the exact changes made

$ git log -G'login'
$ git log -G'login' -i # case insensitive
$ git log -p -G'login' # can be combined with -p flag

Limit log to patches containing a RegEx

$ git log --grep 'WWW-1234' 
$ git log --grep 'route' --grep 'workout' # matches any
$ git log --grep 'route' --grep 'workout' --all-match  # matches all
$ git log --grep 'route' -grep 'workout' --invert-grep # matches none

Limit log to patches whose log message matches a RegEx

$ git log -L 1,20:settings.py  # limit to certain lines
$ git log --no-merges          # ignore merge commits
$ git log --since='2018-01-01' # limit by date
$ git log --until='2018-01-01' 
$ git log --since='2018-01-01' --until='2018-04-01'
$ git log --author='Adam Giese' # limit by author
$ git log --reverse             # chronological order

Other useful flags include, but are not limited to...

$ git log --grep 'WWW-1234'

Finding commits associated with a JIRA ticket

$ git log --patch --follow -- 'settings.py'
$ git log -L 84,114:settings.py

Viewing the history of a file or a line range

$ git log --patch --since='2 weeks ago' -G'geoip' -i

Find all recent patches with a regex

$ git log -G'nike_password' --since='2 weeks ago'

$ git diff

Prints differences between the working tree and the index. This is the most common usage, but git diff is capable of much more.

$ git diff master

Prints differences between the working tree and the selected branch. This is useful for figuring out where you may have broken something.

$ git diff master..feature 
$ git diff ..origin/master # Ommited argument uses HEAD
$ git diff ..HEAD~         # Compares current commit to previous

Prints differences between any two commits.

$ git diff master..feature/year-in-review -- ':/src/**.jsx'

By adding a pathspec, you can limit the scope of the diff to the specified path. This is useful if you have a single file or directory you'd like to compare

$ git diff

"Oh shit, what just broke?"

$ git diff master

"Oh shit, what broke since diverging from master?"

$ git diff HEAD~

"Oh shit, what broke last commit?"

$ git diff master -- workout.py

"Oh shit, what broke in this particular file?"

$ git grep route -- 'README.md' 
$ git grep route -- 'src' 
$ git grep route -- '**/*.js' 
$ git grep route -- ':/' 
$ git grep -i route feature-branch -- ':/src/**/*.js' 

including a pathspec

$ git bisect run docker-compose run tests

grab some ☕️ and let your computer do the work