Git is a free and open source
distributed version control system . It is designed to handle a small to very
large projects with speed and efficiency. To read more details and changes
about Git 2.9.1 read
Git release notes. If you are using a
Git repository for your development, then you must required a git client on
your system and you need to install git client on your workstation system
This tutorial will help you to install
git core 2.9.1 on CentOS/RHEL 7/6/5 operating systems using source code. For
beginners visit Git console (http://try.github.io/levels/1/challenges/1) on
your browser and learn Git uses and command line tips.
Step
1 – Install Required Packages
Before
installing Git from source code, make sure you have already installed required
packages on your system. If not use
following command to install required packages.
# yum
install curl-devel expat-devel gettext-devel openssl-devel zlib-devel
# yum
install gcc perl-ExtUtils-MakeMaker
Step
2 – Download and Install Git
Download
latest Git source code from kernel git or simply use following command to
download Git 2.9.1.
# cd
/usr/src
# wget
https://www.kernel.org/pub/software/scm/git/git-2.9.1.tar.gz
# tar xzf
git-2.9.1.tar.gz
After
downloading and extracting Git source code, Use following command to compile
source code.
# cd
git-2.9.1
# make
prefix=/usr/local/git all
# make
prefix=/usr/local/git install
Step
3 – Setup Environment
After
installation of git client. Now you must need to set binary in system
environment.
So edit
/etc/bashrc file and add below content to it
# export
PATH=$PATH:/usr/local/git/bin
Now
execute below command to reload configuration in current environment.
# source
/etc/bashrc
After completing
above steps. Let’s use following command to check current git version.
# git
--version
If it is
showing older version then grep and remove it
# rpm -qa
| grep git
git-1.8.3.1-6.el7_2.1.x86_64
# rpm -e
--nodeps git-1.8.3.1-6.el7_2.1.x86_64
check for
newer version
# git
--version
git
version 2.9.1
Setting up User Identity:
# git
config --global user.name "John Doe"
# git
config --global user.email peterdrucker@sample.com
# git
config --global color.ui true
# git
config --global color.status auto
# git
config --global color.branch auto
# git
config --global core.editor vim
# git
config --global merge.tool vimdiff
# git
config –list
Git – Life Cycle:
Step
4 – Create user and base repository
Create New
user:
# groupadd
devs
# useradd
-G devs -d /home/sameer -m -s /bin/bash
sameer
# password
sameer
Create a
Base repository:
# pwd
/home/sameer
# mkdir project.git
# cd
project.git/
# ls
# git
--bare init
Initialized
empty Git repository in /home/sameer/project.git/
# ls
branches config
description HEAD hooks
info objects refs
Step
5 – Configure git client on your local windows machine
Download
and install git client and install
Open git gui
and select - > create new repository
or Open existing repository.
Generate
private/public keys for the SSH server
Generate
key with secure phrase @ 4096 encryption
Install
the new private ssh key on the remote server
private
ssh key, remote server, authorized_keys
Install
the new private ssh key into git client
Open ->
Remote -> select Add then enter Name, location of remote server
(Location:
ssh://username@192.168.1.7:22/home/user/repo/project.git)
Push your
first commit to create the master remote-> push ->master
Done...
* Note:
error:
bash: git-receive-pack: command not found
fatal:
Could not read from remote repository.
Adding
this to my .bashrc via PATH=$PATH:/new/path/here worked for me
vi
/home/user/.bashrc
PATH=$PATH:/usr/local/git/bin
source
/etc/bashrc
Note:
You can
easily restrict the git user to only doing Git activities with a limited shell
tool called git-shell that comes with Git. If you set this as your git user’s
login shell, then the git user can’t have normal shell access to your server.
To use this, specify git-shell instead of bash or csh for your user’s login
shell. To do so, you must first add git-shell to /etc/shells if it’s not
already there:
# cat
/etc/shells # see if `git-shell` is
already in there. If not...
# which
git-shell # make sure git-shell is
installed on your system.
# sudo vim
/etc/shells # and add the path to
git-shell from last command
Now you
can edit the shell for a user using chsh <username>:
# sudo
chsh git # and enter the path to
git-shell, usually: /usr/bin/git-shell
Now, the
git user can only use the SSH connection to push and pull Git repositories and
can’t shell onto the machine. If you try, you’ll see a login rejection like
this:
# ssh
git@gitserver
fatal:
Interactive git shell is not enabled.
hint:
~/git-shell-commands should exist and have read and execute access.
Connection
to gitserver closed.
Now Git
network commands will still work just fine but the users won’t be able to get a
shell. As the output states, you can also set up a directory in the git user’s
home directory that customizes the git-shell command a bit. For instance, you
can restrict the Git commands that the server will accept or you can customize
the message that users see if they try to SSH in like that. Run git help shell
for more information on customizing the shell.
Git usage and example:
To create a new git repository, create a folder and apply this command
# git init
To create a working copy to a local repository
# git clone /path/to/repository
To creat a working copy from remote repository
# git clone username@host:/path/to/repository
Workflow:
local repository consists of three trees maintained by git.
1. Working directory (holds actual files)
2. Index (staging area)
3. HEAD (points to last commit)
Add and commit:
add changes to the index using
# git add <filename>
# git add *
To commit changes to HEAD
# git commit -m "commit message"
To connect repository to remote server
# git remote add origin <server>
To send changes to remote repository
# git push origin master
To create a local branch and swith to it
# git checkout -b <branch>
To switch back to master branch
# git checkout master
To delete the branch
# git branch -d <branch>
To push branch to remote repository
# git push origin <branch>
To fetch and merge remote changes to local repository
# git pull
To merge another branch into active branch
# git merge <branch>
Mark them as merged with before merging changes
# git add filename
To preview changes and differences
# git diff <source_branch> <target_branch>
To create a new tags for software releases with commit id
# git tag 1.0.0 1b2e1d63ff
To see only the commits of a certain author
# git log --author=bob
To see a very compressed log where each commit is one line
# git log --pretty=oneline
To see an ASCII art tree of all the branches
# git log --graph --oneline --decorate --all
To see whichfiles have changed
# git log --name-status
To replace changes in your working repository
# git checkout --<filename>
To drop all your local changes and commits, fetch the latest history from the server and point your local master branch at it
# git fetch origin
# git reset --hard origin/master
