Open Source Comes to Campus/Resources: Difference between revisions

imported>Paulproteus
imported>Paulproteus
=== Version Control Demo ===
 
(This talk is assuming you are speaking at Wellesley College. You're probably not going to be speaking at Wellesley, so you'll need to make a handful of changes!)
Start by saying:
 
* In open source software, people use version control to keep track of files as they change. To give you a sense of what this is for, how many of you have worked on group programming projects? (A few hands raise up.) One common way to do that is to email around copies of a file you're working on. When every person working on a project uses version control, they have their own copy of the project and they can make whatever changes they want, and they can synchronize with the main version....
* How did you keep track of different people working on different files?
** Some people will say they emailed around different copies of files.
** Others may say that they had people all working in person and talking about changes.
* How well did that work out?
** Attendees will typically chuckle.
* So, yeah, one common way to do that is to email around copies of a file you're working on. A different way is to use what's called version control, where there is a system for tracking different versions of a file. The most popular tools let every contributor keep a copy of the project on their own computer, making whatever changes they want, and eventually synchronizing with the rest of the team.
* To talk about version control, I want to show you how version control works for purely text documents. So let's look at the Wikipedia page for Wellesley College.
* (Navigate web browser to http://en.wikipedia.org/wiki/Wellesley_College )
* So one of the great things about Wikipedia is that the system keeps every track of every version of every article. The wiki system is a version control system, too. If you click on the "Edit" tab, you can see the built in way to edit every article. Let's take a look at the ''history'' tab here. (click history tab)
* (find yourself at http://en.wikipedia.org/w/index.php?title=Wellesley_College&action=history ; zoom in so it's large enough for people to see; make it really enormous)
* So here, you can see a little heading for every version of the page, including (mouse over the date) the time and date of that version, who madesaved htat version, and a brief summary of what the changes are.. Here, the most recent version says +73 -- that means that 73 characters were added in that revision.
* One standard feature of version control tools is to be able to see each version of the file. On Wikipedia, you can do that by clicking on the date.
** (click on the most recent edit, taking you to e.g. http://en.wikipedia.org/w/index.php?title=Wellesley_College&oldid=559029901 )
** You can see the box at the top that says, "This is the current revision of the page." The real thing going on here is that we're using an identifier for the page that will never change, even if the page gets edited, because we're looking at the particular revision.
* Let's hit back, and take a look at an older version that has an edit summary. In this case, we see they say they added a note about New Zealand. When we click the date (Click the date)... and load the page, we can see visually that the page seems to have a note about New Zealand. But we don't know just from looking at this version of the page if maybe they made other changes.
* You folks already saw diffs, and like most version control tools, Wikipedia lets you see a diff between the two pages. It's line-based, like a lot of tools used in programming. Let's click back... (back to http://en.wikipedia.org/w/index.php?title=Wellesley_College&action=history ) and instead of clicking on the date, we'll select this revision as the first item selected, and the one right after it as the one we want to diff against. When we click "Compare selected revisions", it takes us to ...
 
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