[ubuntu ~]$ git --version
git version 1.8.1.2

#SET USERNAME
[jerry@CentOS project]$ git config --global user.name "Jerry Mouse"

#SET EMAILID
[jerry@CentOS project]$ git config --global user.email "jerry@tutorialspoint.com"

# --global

#LIST GIT SETTINGS
[jerry@CentOS ~]$ git config --list

# add new group
[root@CentOS ~]# groupadd dev

# add new user
[root@CentOS ~]# useradd -G devs -d /home/gituser -m -s /bin/bash gituser

# change password
[root@CentOS ~]# passwd gituser

[gituser@CentOS ~]$ pwd
/home/gituser

[gituser@CentOS ~]$ mkdir project.git

[gituser@CentOS ~]$ cd project.git/

[gituser@CentOS project.git]$ ls

[gituser@CentOS project.git]$ git init
Initialized empty Git repository in /home/gituser-m/project.git/

[gituser@CentOS project.git]$ ls
branches config description HEAD hooks info objects refs

[jerry@CentOS ~]$ mkdir jerry_repo

[jerry@CentOS ~]$ cd jerry_repo/

[jerry@CentOS jerry_repo]$ git clone gituser@git.server.com:project.git

#WRITE A NEW CODE IN YOUR REPO.

[jerry@CentOS project]$ git status -s
?? string
?? string.c

[jerry@CentOS project]$ git add string.c

#string.c IS ADDED TO THE STAGING AREA

[jerry@CentOS project]$ git status -s
A string.c
?? string

#IF WE OMMIT -m Git will open a text editor where we can write multiline commit message.
[jerry@CentOS project]$ git commit -m 'Implemented my_strlen function'
[master cbe1249] Implemented my_strlen function
1 files changed, 24 insertions(+), 0 deletions(-)
create mode 100644 string.c

[jerry@CentOS project]$ git log
commit cbe1249b140dad24b2c35b15cc7e26a6f02d2277
Author: Jerry Mouse <jerry@tutorialspoint.com>
Date: Wed Sep 11 08:05:26 2013 +0530

Implemented my_strlen function


commit 19ae20683fc460db7d127cf201a1429523b0e319
Author: Tom Cat <tom@tutorialspoint.com>
Date: Wed Sep 11 07:32:56 2013 +0530

Initial commit

[jerry@CentOS project]$ git log
commit cbe1249b140dad24b2c35b15cc7e26a6f02d2277
Author: Jerry Mouse <jerry@tutorialspoint.com>
Date: Wed Sep 11 08:05:26 2013 +0530

Implemented my_strlen function

[jerry@CentOS project]$ git show cbe1249b140dad24b2c35b15cc7e26a6f02d2277
commit cbe1249b140dad24b2c35b15cc7e26a6f02d2277
Author: Jerry Mouse <jerry@tutorialspoint.com>
Date: Wed Sep 11 08:05:26 2013 +0530

Implemented my_strlen function


diff --git a/string.c b/string.c
new file mode 100644
index 0000000..187afb9
--- /dev/null
+++ b/string.c
@@ -0,0 +1,24 @@
+#include <stdio.h>
+
+int my_strlen(char *s)
+{
   +
   char *p = s;
   +
   +
   while (*p)
   + ++p;
   + return (p -s );
   +
}
+

#Git diff shows '+' sign before lines, which are newly added and '−' for deleted lines.

[jerry@CentOS project]$ git diff
diff --git a/string.c b/string.c
index 187afb9..7da2992 100644
--- a/string.c
+++ b/string.c
@@ -1,6 +1,6 @@
#include <stdio.h>

-int my_strlen(char *s)
+size_t my_strlen(char *s)
{
   char *p = s;
   @@ -18,7 +18,7 @@ int main(void)
};
for (i = 0; i < 2; ++i)
{
   - printf("string lenght of %s = %d\n", s[i], my_strlen(s[i]));
   + printf("string lenght of %s = %lu\n", s[i], my_strlen(s[i]));
   return 0;
}

[jerry@CentOS project]$ git log
commit cbe1249b140dad24b2c35b15cc7e26a6f02d2277
Author: Jerry Mouse <jerry@tutorialspoint.com>
Date: Wed Sep 11 08:05:26 2013 +0530

Implemented my_strlen function


commit 19ae20683fc460db7d127cf201a1429523b0e319
Author: Tom Cat <tom@tutorialspoint.com>
Date: Wed Sep 11 07:32:56 2013 +0530

Initial commit

#The amend operation changes the last commit including your commit message.
#it creates a new commit ID.
[jerry@CentOS project]$ git status -s
M string.c
?? string

[jerry@CentOS project]$ git add string.c

[jerry@CentOS project]$ git status -s
M string.c
?? string

[jerry@CentOS project]$ git commit --amend -m 'Changed return type of my_strlen to size_t'
[master d1e19d3] Changed return type of my_strlen to size_t
1 files changed, 24 insertions(+), 0 deletions(-)
create mode 100644 string.c

[jerry@CentOS project]$ git log
commit d1e19d316224cddc437e3ed34ec3c931ad803958
Author: Jerry Mouse <jerry@tutorialspoint.com>
Date: Wed Sep 11 08:05:26 2013 +0530

Changed return type of my_strlen to size_t


commit 19ae20683fc460db7d127cf201a1429523b0e319
Author: Tom Cat <tom@tutorialspoint.com>
Date: Wed Sep 11 07:32:56 2013 +0530

Initial commit

#The Push operation stores data permanently to the Git repository.
#After push operation, other developers can see Jerry’s changes.
[jerry@CentOS project]$ git push origin master
Counting objects: 4, done.
Compressing objects: 100% (3/3), done.
Writing objects: 100% (3/3), 517 bytes, done.
Total 3 (delta 0), reused 0 (delta 0)
To gituser@git.server.com:project.git
19ae206..d1e19d3 master −> master

[jerry@CentOS project]$ git push origin master
To gituser@git.server.com:project.git
! [rejected]
master −> master (non-fast-forward)
error: failed to push some refs to 'gituser@git.server.com:project.git'
To prevent you from losing history, non-fast-forward updates were rejected
Merge the remote changes before pushing again. See the 'Note about
fast-forwards' section of 'git push --help' for details.

[jerry@CentOS project]$ git pull
remote: Counting objects: 5, done.
remote: Compressing objects: 100% (3/3), done.
remote: Total 3 (delta 1), reused 0 (delta 0)
Unpacking objects: 100% (3/3), done.
From git.server.com:project
d1e19d3..cea2c00 master −> origin/master
First, rewinding head to replay your work on top of it...
Applying: Added my_strcpy function

#CANT PUSH BEFORE PULL

[jerry@CentOS project]$ git push origin master
Counting objects: 5, done.
Compressing objects: 100% (3/3), done.
Writing objects: 100% (3/3), 455 bytes, done.
Total 3 (delta 1), reused 0 (delta 0)
To gituser@git.server.com:project.git
cea2c00..e86f062 master −> master

[jerry@CentOS project]$ git status -s
M string.c
?? string

[jerry@CentOS project]$ git stash
Saved working directory and index state WIP on master: e86f062 Added my_strcpy function
HEAD is now at e86f062 Added my_strcpy function

#your working directory is clean and all the changes are saved on a stash
[jerry@CentOS project]$ git status -s
?? string

[jerry@CentOS project]$ git stash list
stash@{0}: WIP on master: e86f062 Added my_strcpy function

[jerry@CentOS project]$ git status -s
?? string

[jerry@CentOS project]$ git stash pop
# On branch master
# Changed but not updated:
# (use "git add ..." to update what will be committed)
# (use "git checkout -- ..." to discard changes in working directory)
#
#
modified: string.c
#
# Untracked files:
# (use "git add ..." to include in what will be committed)
#
#
string
no changes added to commit (use "git add" and/or "git commit -a")
Dropped refs/stash@{0} (36f79dfedae4ac20e2e8558830154bd6315e72d4)

[jerry@CentOS project]$ git status -s
M string.c
?? string

[tom@CentOS project]$ pwd
/home/tom/project

[tom@CentOS project]$ ls
README string string.c

[tom@CentOS project]$ mkdir src

[tom@CentOS project]$ git mv string.c src/

[tom@CentOS project]$ git status -s
R string.c −> src/string.c
?? string

[tom@CentOS project]$ git commit -m "Modified directory structure"

[master 7d9ea97] Modified directory structure
1 files changed, 0 insertions(+), 0 deletions(-)
rename string.c => src/string.c (100%)

[tom@CentOS project]$ git push origin master
Counting objects: 4, done.
Compressing objects: 100% (2/2), done.
Writing objects: 100% (3/3), 320 bytes, done.
Total 3 (delta 0), reused 0 (delta 0)
To gituser@git.server.com:project.git
e86f062..7d9ea97 master −> master

[jerry@CentOS project]$ pwd
/home/jerry/jerry_repo/project

[jerry@CentOS project]$ ls
README src

[jerry@CentOS project]$ cd src/

[jerry@CentOS src]$ git add Makefile

[jerry@CentOS src]$ git mv string.c string_operations.c

#Git is showing R before file name to indicate that the file has been renamed.
[jerry@CentOS src]$ git status -s
A Makefile
R string.c −> string_operations.c

[tom@CentOS src]$ ls
Makefile string_operations string_operations.c

[tom@CentOS src]$ git rm string_operations
rm 'src/string_operations'

[tom@CentOS src]$ git commit -a -m "Removed executable binary"

[master 5776472] Removed executable binary
1 files changed, 0 insertions(+), 0 deletions(-)
delete mode 100755 src/string_operations

[jerry@CentOS src]$ pwd
/home/jerry/jerry_repo/project/src

[jerry@CentOS src]$ git status -s
M string_operations.c

[jerry@CentOS src]$ git checkout string_operations.c

[jerry@CentOS src]$ git status –s

[tom@CentOS src]$ pwd
/home/tom/top_repo/project/src

[tom@CentOS src]$ ls -1
Makefile
string_operations.c

[tom@CentOS src]$ rm string_operations.c

[tom@CentOS src]$ ls -1
Makefile

#Git is showing the letter D before the filename.
[tom@CentOS src]$ git status -s
D string_operations.c

[tom@CentOS src]$ git checkout string_operations.c

[tom@CentOS src]$ ls -1
Makefile
string_operations.c

[tom@CentOS src]$ git status -s

tom@CentOS src]$ pwd
/home/tom/top_repo/project/src
# Unmodified file

[tom@CentOS src]$ git status -s

# Modify file and view it’s status.
[tom@CentOS src]$ git status -s
M string_operations.c

[tom@CentOS src]$ git add string_operations.c

[tom@CentOS src]$ git checkout HEAD -- string_operations.c

[tom@CentOS src]$ git status -s

[jerry@CentOS src]$ git branch new_branch

[jerry@CentOS src]$ git branch
* master
new_branch

#SWITCH BETWEEN BRANCH
[jerry@CentOS src]$ git checkout new_branch
Switched to branch 'new_branch'
[jerry@CentOS src]$ git branch
master
* new_branch

#Create and Switch Branch
[jerry@CentOS src]$ git checkout -b test_branch
Switched to a new branch 'test_branch'

[jerry@CentOS src]$ git branch
master
new_branch
* test_branch

#delete branch
[jerry@CentOS src]$ git branch
master
new_branch
* test_branch

[jerry@CentOS src]$ git checkout master
Switched to branch 'master'

[jerry@CentOS src]$ git branch -D test_branch
Deleted branch test_branch (was 5776472).

[jerry@CentOS src]$ git branch
* master
new_branch

#rename branch
[jerry@CentOS src]$ git branch
* master
new_branch

[jerry@CentOS src]$ git branch -m new_branch wchar_support
[jerry@CentOS src]$ git branch
* master
wchar_support

#MERGE BRANCHES
[jerry@CentOS src]$ git push origin wchar_support   <−−− Observer branch_name
Counting objects: 7, done.
Compressing objects: 100% (4/4), done.
Writing objects: 100% (4/4), 507 bytes, done.
Total 4 (delta 1), reused 0 (delta 0)
To gituser@git.server.com:project.git
* [new branch]
wchar_support -> wchar_support

[tom@CentOS src]$ pwd
/home/tom/top_repo/project/src

[tom@CentOS src]$ git log origin/wchar_support
commit 64192f91d7cc2bcdf3bf946dd33ece63b74184a3
Author: Jerry Mouse <jerry@tutorialspoint.com>
Date: Wed Sep 11 16:10:06 2013 +0530

Added w_strlen function to return string lenght of wchar_t string


commit 577647211ed44fe2ae479427a0668a4f12ed71a1
Author: Tom Cat <tom@tutorialspoint.com>
Date: Wed Sep 11 10:21:20 2013 +0530

Removed executable binary

[tom@CentOS project]$ git branch
* master

[tom@CentOS project]$ pwd
/home/tom/top_repo/project

[tom@CentOS project]$ git merge origin/wchar_support
Updating 5776472..64192f9
Fast-forward
src/string_operations.c | 10 ++++++++++
1 files changed, 10 insertions(+), 0 deletions(-)

$ mkdir git-merge-test
$ cd git-merge-test
$ git init .
$ echo "this is some content to mess with" > merge.txt
$ git add merge.txt
$ git commit -am"we are commiting the inital content"
[master (root-commit) d48e74c] we are commiting the inital content
1 file changed, 1 insertion(+)
create mode 100644 merge.txt

$ git checkout -b new_branch_to_merge_later
$ echo "totally different content to merge later" > merge.txt
$ git commit -am"edited the content of merge.txt to cause a conflict"
[new_branch_to_merge_later 6282319] edited the content of merge.txt to cause a conflict
1 file changed, 1 insertion(+), 1 deletion(-)

git checkout master
Switched to branch 'master'
echo "content to append" >> merge.txt
git commit -am"appended content to merge.txt"
[master 24fbe3c] appended content to merge.tx
1 file changed, 1 insertion(+)

$ git merge new_branch_to_merge_later
Auto-merging merge.txt
CONFLICT (content): Merge conflict in merge.txt
Automatic merge failed; fix conflicts and then commit the result.

$ git status
On branch master
You have unmerged paths.
(fix conflicts and run "git commit")
(use "git merge --abort" to abort the merge)

Unmerged paths:
(use "git add <file>..." to mark resolution)

both modified:   merge.txt

$ cat merge.txt
<<<<<<< HEAD
this is some content to mess with
content to append
=======
totally different content to merge later
>>>>>>> new_branch_to_merge_later

# Change the file to:
#this is some content to mess with
#content to append
#totally different content to merge later

git commit -m "merged and resolved the conflict in merge.txt"