The
beauty
of

https://git-scm.com/docs/gitrepository-layout

Command types

porcelain

plumbing

https://git-scm.com/book/en/v2/Git-Internals-Plumbing-and-Porcelain

porcelain commands

the shiny surface

meant for the end user

housekeeping included

usually used for command line

plumbing commands

get your hands dirty

meant for the craftsmen

where the real work is done

intended to be upward compatible

use it for scripts

Locations

working tree

index

repository

remote

working tree

trees and blobs on local filesystem

based on a branch or other commit

can be "clean" or "dirty"

index

staging area

objects stored, but not commited

manage what the next commit will do

repository

everything Git knows about your files

usually the ".git" subdir of the working tree

may be "bare", i.e. without a working tree

https://jwiegley.github.io/git-from-the-bottom-up/

remote

other repository "somewhere" else

fetch / pull to get changes

push to spread changes

Objects

include header with type and length

sha1 guaranties integrity

content addressed

compressed

https://git-scm.com/book/en/v2/Git-Internals-Git-Objects

Object types

blobs

trees

commits

(annotated) tags

References

pointers to objects

just ordinary text files

reflogs track changes temporarily

https://git-scm.com/book/en/v2/Git-Internals-Git-References

Reference types

heads (aka branches)

(simple) tags

HEAD, FETCH_HEAD etc.