Git is a good alternative to Mercurial, and of course SVN or CVS if you’re still using stone age tools, so in this post I’ll show you how to compile, install and use git with Rails.

Installing git on Mac OS X

First compile and install git:

   1  cd /usr/local/src
   2  wget http://kernel.org/pub/software/scm/git/git-1.5.4.4.tar.bz2
   3  tar jxvf git-1.5.4.4.tar.bz2
   4  cd git-1.5.4.4
   5  make prefix=/usr/local all
   6  make prefix=/usr/local test && echo $?
   7  sudo make prefix=/usr/local install

Installing git on Debian

On a Debian installation install git by first executing the following commands:

$ sudo apt-get install git-core

Note that the package name is git-core not git.

If you want the latest and greatest version, you first need to install the dependencies (note that you can leave out tk and expat):

   1  sudo apt-get install curl
   2  sudo apt-get install libcurl3
   3  sudo apt-get install libcurl3-dev
   4  sudo apt-get install tk8.4
   5  sudo apt-get install cpio expat
   6  sudo apt-get install zlib
   7  sudo apt-get install build-essential
   8  sudo apt-get install zlib1g-dev 
   9  sudo apt-get install asciidoc
  10  sudo apt-get install xmlto

Then compile and install:

   1  NO_EXPAT=yes NO_SVN_TESTS=yes NO_IPV6=yes NO_TCLTK=yes make -j2 prefix=/usr all
   2  NO_EXPAT=yes NO_SVN_TESTS=yes NO_IPV6=yes NO_TCLTK=yes make -j2 prefix=/usr install

Configuring git

Run these commands to tell git your name and email:

   1  git config --global user.name "u name"
   2  git config --global user.email x@x.com

Otherwise, you might get this error:

   1  *** Environment problem:
   2  *** Your name cannot be determined from your system services (gecos).
   3  *** You would need to set GIT_AUTHOR_NAME and GIT_COMMITTER_NAME
   4  *** environment variables; otherwise you won't be able to perform
   5  *** certain operations because of "empty ident" errors.
   6  *** Alternatively, you can use user.name configuration variable.
   7  
   8  fatal: empty ident  <........@........com> not allowed
   9  fatal: The remote end hung up unexpectedly

If you like colorized command output execute these commands:

   1  git config --global color.diff auto
   2  git config --global color.status auto
   3  git config --global color.branch auto

Using git

If all goes well, change to your project directory and run the following commands:

   1  git init

This creates the git repository, so we’re now ready to start adding files to it, but first we need to create the git ignore file, which tells git to ignore certain files completely:

   1  cat <<EOF<<EOF > .gitignore 
   2  config/database.yml
   3  db/*.sqlite3
   4  log/*.log
   5  tmp/**/*
   6  .DS_Store
   7  doc/api
   8  doc/app
   9  EOFEOF

By default git doesn’t add empty directories—sucks if you ask me—so we’ll create a dummy file in all empty directories with the find and touch commands:

   1  find . \( -type d -empty \) -and \( -not -regex ./\.git.* \) -exec touch {}/.gitignore \; 

Importing files

We’re now ready to start adding and commiting files, so without thinking execute:

   1  git add .
   2  git commit -m 'initial import'

This creates the git repository, adds and commits all files that are in the current folder.

Using remote repositories

If you’re like me you’ll want to use a remote repository, so let’s continue the exercise by creating the repository folder on the remote server (Note that commands are executed on the remote server from now on):

   1  mkdir /var/lib/git/repositories/project_name

We want the folder to be accessible by users belonging to the git group only:

   1  addgroup git
   2  chown root.git /var/lib/git/repositories/project_name
   3  chmod 770 /var/lib/git/repositories/project_name

Now add yourself—or the user you’ll be using to connect to the remote server—to the git group:

   1  usermod -a -G git your_username

Alternatively create a new user:

   1  useradd -g git your_username

Now we’re finally ready to copy the local repository to the remote server, which is done with the scp command (Note that commands are executed locally again from now on):

   1  scp -rp .git user@server://var/lib/git/repositories/project_name

To let git know that this repository exists we’ll use the git remote command:

   1  git remote add project_name ssh://server/var/lib/git/repositories/project_name

This adds the information to .git/config, which might be good to have a quick look at.

Note that if you’re using a non-standard SSH port you need to add the following to your ~/.ssh/config file:

   1  Host server
   2    Port 1234

Commit files and push them to the remote server

Now change a file and commit and push the changes to the remote server:

   1  git commit -m "Me be sleepy"
   2  git push project_name

If you get an error such as this it means you need to install git:

   1  $ git push project_name
   2  username@server's password: 
   3  sh: git-receive-pack: command not found
   4  fatal: The remote end hung up unexpectedly

That’s all…

Miscellaneous problems

error: unable to create temporary sha1 filename ./objects/obj_FUu2jb: Permission denied

Resources

http://jointheconversation.org/railsgit

http://devblog.michaelgalero.com/2007/12/17/my-git-notes-for-rails/

http://railscasts.com/episodes/96

http://groups.google.com/group/rails-oceania/browse_thread/thread/2c8611dc93917952/e175f72310823547

http://www.kernel.org/pub/software/scm/git/docs/tutorial.html

http://scie.nti.st/2007/11/14/hosting-git-repositories-the-easy-and-secure-way

If you’ve compiled Ruby from source, you might get this error when executing script/console:

   1  /usr/local/lib/ruby/1.8/irb/completion.rb:10:in `require': no such file to load -- readline (LoadError)

One way of fixing this is to compile readline, which is distributed along with the Ruby source:

   1  cd /opt/src/ruby-1.8.5-p2/ext/readline
   2  ruby extconf.rb
   3  make
   4  sudo make install

This works even after compiling Ruby, so no need to recompile… If you’re wondering what readline is then this quote from the project homepage sums it up in one sentence: “The GNU Readline library provides a set of functions for use by applications that allow users to edit command lines as they are typed in.”