Git is a distributed version control system.
Git is free software.

$ git status
# On branch master
# Changes not staged for commit:
#   (use "git add <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#    modified:   readme.txt
#
no changes added to commit (use "git add" and/or "git commit -a")

$ git diff readme.txt 
diff --git a/readme.txt b/readme.txt
index 46d49bf..9247db6 100644
--- a/readme.txt
+++ b/readme.txt
@@ -1,2 +1,2 @@
-Git is a version control system.
+Git is a distributed version control system.
 Git is free software.

$ git add readme.txt

$ git status
# On branch master
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#       modified:   readme.txt
#

$ git commit -m "add distributed"
[master ea34578] add distributed
 1 file changed, 1 insertion(+), 1 deletion(-)

$ git status
# On branch master
nothing to commit (working directory clean)