Set a global .gitignore

git config --global core.excludesfile ~/.gitignore

Ignore files for emacs

*~
\#*\#

Ignore files for ensime

.ensime
.ensime_cache

Ignore files for eclipse

.settings
.classpath
.cache-main
.cache-tests
.project

Setting username/email

Globally

git config --global user.name "My Name"
git config --global user.email "[email protected]"

Drop the --global for a per-repo configuration.

How to stage pieces of a diff (instead of whole thing)

git add -p <filepath>