Getting Started with
(Distributed) Version Control
Because what other tools have a blame
command?
John Paulett
jhcore.com
April 3, 2009 1

Collaboration
Bob adds foo() to main.c while Alice edits
bar() in main.c. How do they merge?
Please do not share code via Windows file
sharing!
April 3, 2009 2

History
\"Oops, we screwed up the release, can we
roll back to the last production version?\"
“Who added this bug?”
April 3, 2009 3

Backup
\"The Photoshop keygen gave me a virus.\"
Sharing files between computers
April 3, 2009 4

Personally
Open source projects
Personal projects (master's thesis code)
School files (papers, assignments)
Config files (~/.ssh/config, ~/.hgrc)
April 3, 2009 5

Centeralized vs Decentralized
Cathedral vs Bazaar
Offline commits
More atomic commits
●
Forking is encouraged
Can keep private until ready
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http://en.wikipedia.org/wiki/index.html?curid=755487
April 3, 2009 6

VCS Tools
cp -R project project.old
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RCS
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CVS
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Subversion
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Perforce
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Visual SafeSource
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ClearCase
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...
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April 3, 2009 7

Distributed VCS Tools
Mercurial Plastic SCM
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Git SVK
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Bazaar Codeville
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Monotone GNU arch
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Darcs Bitkeeper
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...
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April 3, 2009 8

Which one?
The new “vim vs emacs”
http://xkcd.com/378/
(emacs is better)
April 3, 2009 9

Mercurial
OpenJDK
●
Solaris
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Python
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Mozilla
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Netbeans
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April 3, 2009 10

Workflow
1. Checkout / Start repo
2. Add / Remove / Edit files
3. Commit your changes
4. Push changes
5. Update / Merge
6. Go to #2
April 3, 2009 11

Simple Example
# checkout the repository
hg clone http://bitbucket.org/johnpaulett/python-hl7/
# add the file server.py to be under version control
hg add server.py
# commit the file
hg commit -m \"Added a single threaded HL7 socket
server.\"
April 3, 2009 12

Simple Example
# Send my changes to bitbucket
hg push
# Pull others' changes from bitbucket
hg pull
hg update
# Merge in anyone else's changes
hg merge
April 3, 2009 13

Useful Commands
Start a repository:
hg init my-emr
Find out who changed what in which
version:
hg blame
hg log
April 3, 2009 14

But I Hate the Command Line
TortoiseHg
April 3, 2009 15

But I Hate the Command Line
MercurialEclipse
April 3, 2009 16

Being a DVCS Dog
\"On the Internet, nobody knows that you're
a dog.\"
hgsubversion
git-svn
April 3, 2009 17
New Yorker, 1993

Hosting
BitBucket (or GitHub for git)
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Sourceforge
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hg serve
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SSH
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hgweb (via Apache)
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April 3, 2009 18

April 3, 2009 19

Bad Commit Messages
Not Atomic
“Fixed a few bugs in the interface.
Added an ID field. Removed a couple
unnecessary functions. Refactored the
context check.”
Not Specific
“Fixed some bugs.”
http://lbrandy.com/blog/2009/03/writing-better-commit-messages/
April 3, 2009 20

Customizing
hgrc
Set locations, username, plugins
.hgignore
Ignore unwanted files (*.class, *.pyc,
*.log)
April 3, 2009 21

More Info
http://www.slideshare.net/johnpaulett/getting-started-with-
●
distributed-version-control
http://www.selenic.com/mercurial/wiki/
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http://betterexplained.com/articles/intro-to-distributed-version-
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control-illustrated/
http://bitbucket.org/
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http://joshcarter.com/productivity/svn_hg_git_for_home_directory
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http://lbrandy.com/blog/2009/03/writing-better-commit-messages/
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http://bitbucket.org/mercurialeclipse/main/wiki/Home
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http://bitbucket.org/durin42/hgsubversion/wiki/Home
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http://bitbucket.org/tortoisehg/stable/wiki/Home
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April 3, 2009 22