VIDEO:http://dl.dropbox.com/u/3037689/lectures/rsync.ogg
OK, Let's begin. This talk is about rsync, a very useful synchronization tool.
So first of all, I want to have a look at what wikipeida tells us.
rsync is a software application for Unix systems which synchronizes files and directories from one location to another while minimizing data transfer using delta encoding when appropriate. An important feature of rsync not found in most similar programs/protocols is that the mirroring takes place with only one transmission in each direction.
AH...Anyway I do not think it is really important in this talk. SO... I just want to say Delta Encoding is really a nice feather, because every time it only transfer the diffs the diffs between remote side data and local host data, only transfer the different part of the two bulk of data, so that saves a lot of time.
(http://en.wikipedia.org/wiki/Delta_encoding)
Delta encoding is a way of storing or transmitting data in the form of differences between sequential data rather than complete files...Yea, this is what I am talking about. I do not want to talk much here, if you like you can check this page yourself.
Anyway, as long as you have Internet connection, Wikipedia is right there for everybody of us.
go back...go back ... why you do not go back ...
AH, yeah, this is the page of the creator of rsync. Here they are talking about the story about him, about why Linux project move form bitkeeper to git, it actually had much to do with this guy.
And Linus Torvards does not like him really. In one of Linus speeches, actually it was one of google talks ,Torvards said:
However, not everybody agreed with me, they are ugly and stupid, but they caused problems...
And here is the guy ugly and stupid , it actually means this guy—Tridgell.
But...he got a Ph.D, doctorate. and
(http://en.wikipedia.org/wiki/Andrew_Tridgell)
October 2003, The Bulletin magazine judged Tridgell to be Australia's smartest Information and Communications Technology person.He is actually a very smart guy. I means this one(# ^ Torvalds knifes Tridgell) is really interesting, you can have a look at this.
So I actually want to show you Tridgell's web-site(http://www.samba.org/~tridge/)
...the picture, I do not like this guy very much..I.. the dog.. the dog is so beautiful. Golden hair, look at the eyes... what a dish!
Of course this is not the most interesting thing here. I want to show you the graduate courses.
Graduate Courses
* Free and Open Source Software Development
this is really something useful. If you click here, it will take you to the web age (http://cs.anu.edu.au/students/comp8440/) of a university. It is a very formal course, it has course number, or lecture number? So it is actully a lecture of Australia National University. College of Engineering and Computer Science.
And...if you click here, you get to say the lecture pages, you can download the pdf files. You also get video files available. Most stuff here is interesting to us, but problem is the Australian pronunciation, the Australian accent. I do not really like it.
OK, let's go back, I am kind of off-topic, so back..back..
This talk is mainly about rsync, yeah, this is our topic this time. And I just want to show you something practical. If you go to my web-site and you type ...yes http://happypeter.users.sourceforge.net
And if you search rsync, you just type rsync here. Here we go. We have two links here.
rsync sf_rsync
sf here stands for Sourceforge, here we get some useful info about rsync. But this is not what I am going to talk about today.
What I am mainly interested in today is how to use rsync to update my SF web-site. Yea, this is the steps I took to update the web-site. SO if everything I need is this command
rsync -r --delete /var/www/ happypeter@frs.sourceforge.net:/home/userweb/h/ha/happypeter/htdocs
the url of SF, my web-site directory...I can synchronize every thing
here (/var/www) into here (/htdocs)
It is not so difficult. But here I would like to give you some demonstration about how to use this command properly. So first I want to show a demo locally.
Let make htdocs as a local directory. On the local machine, the name
is just htdocs. It just the same thing like this htdocs. But it is on
local machine. So, what I need to do is to use this command and then
directory name...try it, see what will happen. So ... check.... OK,
here we go, we got all the web pages, and not only that, we also got
directories. Directories inside this directory. Here are some file
inside the sub-directory.
So I want to explain -r actually means recursive, or recursively
(type man rsync and /-r to see it)
It means you have file in directory or sub-directories, you will get everything synchronized, nothing will be lost. So everything in /var/www/ got synchronized.
TO BE CONTINUED ...