Set git user information
$ git config --global "myusername"
$ git config --global ""

View git user configuration.
$ git config --list

Initialize/Create a new repository
$ git init

Show new/modified/staged files
$ git status

Shows what changed in file(s)
$ git diff
$ git diff myfirstfile.txt

Shows changes between two commits
git diff

Add files to staging
$ git add myfirstfile.txt

Commit files
$ git commit -m "Add new test file to repo"

Shows all commits made to repository
$ git log

Shows all commits from a specific author
$ git log --author="author or email"

Shows all commits but list commit IDs only
$ git log --oneline

Shows all commits with branches graphically
$ git log --graph

Shows git log with custom output (Credits: Cameron McKenzie on youtube)
$ git log --graph --pretty="%C(yellow) HASH: %h %C(blue)Date: %ad %C(red) Message: %s "

Push commits to remote repo
$ git push

Create new git branch
$ git branch testbranch

Switch to a different branch
$ git checkout testbranch

Create a new branch and checkout in same command
git checkout -b testbranch

Push commit to specific branch
$ git push origin testbranch (origin being the name of repository and testbranch being the name of the branch)

Pull from a specific branch and merge the commits to main branch. If the testbranch is a localbranch, git pull can be skipped.
$ git pull origin testbranch (origin being the name of repository and testbranch being the name of the branch)
$ git merge testbranch -m "commit message for merge"
$ git commit
$ git push

Fetch changes but do not merge the changes
$ git fetch origin master (origin being the name of repository and testbranch being the name of the branch)

Pick a commit from a branch and applying it to another
$ git cherry-pick

As an alternative to branch merge, one can rebase and get latest commits
$ git checkout
$ git rebase master
(Gets all latest commits from master into featurebranch
$ git pull --rebase (performs a fetch + rebase)

Reset commits in git. Not suitable to run in remote repo, since history of commits are lost when reset is done.
soft reset does not delete the files of newer commits when it rolls back commits to old commit
$ git reset --soft

hard reset does a rollback to specified old commit and also destroys files associated new commit.
$ git reset --hard

A new commit to revert the commits to the previous one
$ git revert HEAD

A new commit to revert the commits to a specific commit
$ git revert

List all branches
$ git branch -a

Stash changes modified files
$ git stash

Stash all files, including untracked ones
$ git stash -a

List stashed changes
$ git stash list

Restore stashed changes
$ git stash apply (restores stash but does not clear stash)

Delete stashed changes
$ git stash drop (clears stash)

Restore stashed changes and throw away stash
$ git stash pop

Git stash with a message. Works only on tracked files.
$ git stash save "some stash message"

Restore stash from list of stashes using index number, example, 1 being the index
$ git stash apply stash@{1}
in latest versions: $ git stash apply 1 OR
$ git stash pop stash@{1}

See changes in a specific stash
$ git stash show stash@{1}

Rename branch
$ git branch -m <old branch name> <new branch name>

Delete branch (can be done only after switching to a different branch)
$ git branch -d <branch name>