Devaamo ry

Git training with Devaamo

Otto Kekäläinen Uusi Tehdas / New Factory

Tampere 29.11.2012

slides

updated 1.12.

Outline1. The story of Git2. Basic commands3. Git internals4. Doing it with Github5. Advanced commands6. Git everywhere

1. Story of Git

Git / t/ɡɪ”A silly, incompetent, stupid, annoying or childish person.”

http://en.wiktionary.org/wiki/git

"I'm an egotistical bastard, so I name all my projects after myself.

First Linux, now Git”

Linus Torvalds, PC World. 2012-07-14

Linus needed a new source code revision manager for Linux, and none of the available open source options at

the time where good enough, so he wrote his own in April 2005.

Kernel 2.6.12 was the first release managed by Git and version 1.0 of Git was released in December 2005.

Design goals of Git:● distributed revision management● protection against corruption,

both accidental and hostile● speed

Popularity doubled from 2011 to 2012!

...but adoption would be faster if it was not so difficult to use.

Originally Linus did not intend end users to use Git directly, instead he tried to delegate to somebody else the task of making the actual command line

interface. We are still waiting for it...

Luckily Git has been simplified and documentation has improved over time, but some Git commands

still refer to Git internals that are difficult to grasp.

E.g. git-push: Update remote refs along with associated objects.

2. Basic commands

First obstacle: same terms with different meanings

git initgit add example.txtgit commit -nam “First commit”# fill example.txt with text from http://git-scm.com/git commit -nam “Second commit”

git loggit diff HEAD^

git config --global user.name "John Doe"git config --global user.email johndoe@example.com

git clone git://github.com/Seravo/events-manager-translations.git

# edit filesgit commit -nam “Updated translation”git push

git pull# edit filesgit commit -nam “Implemented X”git push

git blame readme.txt

3. Git internals

Folder /.git contains everything,your / is just the working copy.

Folder /.git contains everything,your / is just the working copy.

When you commit a 2 MB file /example.png,your / will grow to 4 MB...

When you add a file,it goes to the staging area.

The file does not go into theactual history tree until the stage

is committed.

Push and pull and many other commandsare short cuts that act with both

your local repository and the remote repositories.

Image credits Steve Bennet (http://steveko.wordpress.com/2012/02/24/10-things-i-hate-about-git/)

Git tracks content, not files!

SHA-1 everywhere, if you need tochange something in the history,

you have to rebase and build a new history.

4. Doing it with Github

Visit http://try.github.com/

After making your first repository, set up SSH keyfor convenient authentication:

https://help.github.com/articles/generating-ssh-keys

Note: Github is not the only Git hosting site,Gitorious and Bitbucket are popular too.

Exercise:- go to https://github.com/ottok/git-training and fork it- look at the fork under your own Github account and clone it to your laptop- edit names.txt and add yours- push changes back to Github- in Github, do a merge request back to me

Want to put a simple shared repository on any SSH capable server? Create a bare .git with no working files:

git init --bare

Want to have notifications when somebody commits?Put a shell script at .git/hooks/post-receive

5. Advanced commands

Sorry, but default commands not very friendly, so get yourself good cheat cheets and write up your common

commands once you've figured them out..

Image credits Steve Bennet (http://steveko.wordpress.com/2012/02/24/10-things-i-hate-about-git/)

5. Git everywhere

Would you like to store all your files in Git?Git-annex

Diff of binary files?Add in .git/config

[diff "odf"] textconv=odt2txt

See also: http://www-verimag.imag.fr/~moy/opendocument/

Backup entire file systems with Git?Bup

https://github.com/apenwarr/bup

Bug tracker and wiki contents in Git?trac+git

Publish to the web with one commit?gitblog

https://github.com/rsms/gitblog

Open source alternative to Dropbox based on Git?http://sparkleshare.org/

Publish to the web with one commit?gitblog

https://github.com/rsms/gitblog

Open source alternative to Dropbox based on Git?http://sparkleshare.org/

Would you like others to contribute to your software?

Provide easy forking (git clone), easy way to develop new feature (git branch),

and an easy way to send them back (merge request).

Will Git credits replace developers CV's?

Is there anything we can't store and track in Git?

Recommended next reading:Pro Git for $25 on Amazon

Also online athttp://git-scm.com/book

This presentation will be available at seravo.fi/blog

Contact Seravo Oy:n if you need Linux natives to develop and administer

your Linux systems

About the company: seravo.fiAbout the technologies: seravo.fi/blog