How to unstage files?

git rm --cached filename

You can also unstage files recursively by:

git rm -r --cached gen

(2010-05-18)

integration to IDEs

EGit - Eclipse plugin for Git.

branch

You are always in a branch in git.  The branch created with git init command is called 'master'.

You can have multiple branches.  To show all the branches, use git branch.  You can switch to a different branch by git checkout command.

To create a new branch, use git branch branchname.

git checkout -b branchname is a shortcut to create a new branch and switch to it.

git branch -d branchname will delete a specified branch.

What is HEAD?
HEAD is the special symbol to refer the current branch.  A Branch is referred by a head, which is the tip of a branch.

% git branch
  experimental
* master                 <--- There are two branches and currently master branch is selected.
% cat .git/HEAD
ref: refs/heads/master   <--- HEAD is referring the head of master branch.
% git checkout experimental
Switched to branch "experimental"
% cat .git/HEAD
ref: refs/heads/experimental   <--- HEAD is now referring the head of experimental branch.

To see which branch you're using, use git branch.

branch and file modification
When you modify a file in a branch and haven't commited, you cannot switch to a different branch.

Also, file you created will be carried to a branch you switched.

Revert

git revert is used for a different meaning than other version control systems such as svn.

Revert to the last committed state

git reset --hard HEAD

--hard changes the working tree and index.

Revert a single file to the repository version

git checkout -- lib/casserver/localization.rb
git checkout HEAD -- db/development.sqlite3

git setup for Rails project

Create .gitignore file with following content:

log/*.log
tmp/**/*
doc/api
doc/app

If you already committed some of these files, remove them using git rm.

git rm -f log/development.log

Initialize a repository

% cd target
% git init

This commands create a git repository at target/.git.

.git/config - configuration file for the repository.
.git/description - a file used by gitweb utility.

The git index is used as a staging area between a working directory and a git repository.

Files in "Changed but not updated" is not in the index.

Show the list of remote git repositories

% git remote show
origin
upstream

It shows the list of the remote repository names.

To see more details, use -v

% git remote -v show
origin git@github.com:gaku/rubycas-server.git
upstream git://github.com/gunark/rubycas-server.git

Pull a specific version of a file with git

git checkout commit path

git checkout ceb17f9984bd59d2fe30aa9f8834d700b1f59de2 db/development.sqlite3

I got the commit name with git log command.

Is .gitignore not working?

Even though I have the following line in .gitignore file, changes are showing up in git status.

.gitignore doesn't have effect to already tracked files. Remove it from repository (git rm --cached ...) or use git update-index --assume-unchanged.
(2009-06-25)