Version Control System (CVS)

1. Project Version Management with
CVS
Concurrent Versions System
K.Bala Vignesh
kbalavignesh@gmail.com
Indian Linux Users Group ­Chennai
Concurrent Versioning System Indian Linux Users Group­Chennai

2. Versioning Software – Why Bother?
● Projects get messy
● Unnecessary Duplication
● Working with other developers is hard!
● Difficult for comparison
● No Revert Back
Concurrent Versioning System Indian Linux Users Group­Chennai

3. The Goals of Version Management
● Record Keeping
– Any previous version available at any moment
● Collaboration
– Ease synchronization between developers
Concurrent Versioning System Indian Linux Users Group­Chennai

4. History Of CVS
"I created CVS to be able to cooperate with my
students Erik Baalbergen and Maarten Waage on
the ACK (Amsterdam Compiler Kit) C compiler.
The three of us had vastly different schedules
(one student was a steady 9­5
worker, the other
was irregular, and I could work on the project
only in the evenings). Their project ran from July
1984 to August 1985. CVS was initially called
cmt, for the obvious reason that it allowed us to
commit versions independently."
— Dick Grune, Dick Grune's website
Concurrent Versioning System Indian Linux Users Group­Chennai

5. Terminology
Repository
Commit
Sand Box
Update
Sand Box
First Time
Sand Box
Check Out
Concurrent Versioning System Indian Linux Users Group­Chennai

6. The “Repository”
Devi Local Version
1.1
Checkout
Muthu Local Version
1.1
a.php Version 1.1
<?php
echo “Hello World”;
?>
Asha Local Version
1.1
Concurrent Versioning System Indian Linux Users Group­Chennai

7. Make Change and Commit
The “Repository”
I
changed
logic
Devi Local Version
1.2
Commit
Muthu Local Version
1.1
a.php Version 1.1
<?php
echo “Hello World”;
echo “hi”;
?>
Asha Local Version
1.1
Concurrent Versioning System Indian Linux Users Group­Chennai

8. The “Repository”
Devi Local Version
1.2
Update
Muthu Local Version
1.1
I need
Up to
Update Date
Asha Local Version
1.2
Concurrent Versioning System Indian Linux Users Group­Chennai

9. Commit and Conflict
The “Repository”
a.php Version 1.1
<?php
echo “Hello World”;
echo “hi”;
?>
Devi Local Version
1.2
Muthu Local Version
1.1
I Changed
Code.
<?php
print “Hello World”;
?>
Asha Local Version
1.2
Concurrent Versioning System Indian Linux Users Group­Chennai

10. Update and then Commit
The “Repository”
Devi Local Version
1.2
Commit
Error
Muthu Local Version
1.1
Old Version.
So,Update First
Asha Local Version
1.2
Concurrent Versioning System Indian Linux Users Group­Chennai

11. The “Repository”
Devi Local Version
1.2
Conflicts
Update
Muthu Local Version
1.1
Asha Local Version
1.2
Concurrent Versioning System Indian Linux Users Group­Chennai

12. Conflicts
a.php Version 1.1 a.php Version 1.2
<?php
echo “Hello World”;
?>
<?php
echo “Hello World”;
echo “hi”;
?>
<?php
print “Hello World”;
?>
a.php Version 1.1
<?php
echo “Hello World”;
?>
Update
Conflicts
<?php
<<<<<a.php
print “Hello World”;
=======
Echo “Hello World”;
echo “hi”;
>>>>>>1.2
?>
a.php Version 1.3
<?php
print “Hello World”;
echo “hi”;
?>
Concurrent Versioning System Indian Linux Users Group­Chennai

13. Conflicts Corrected
The “Repository”
Devi Local Version
1.2
Commit
Muthu Local Version
1.3
a.php Version 1.3
<?php
print “Hello World”;
echo “hi”;
?>
Asha Local Version
1.2
Concurrent Versioning System Indian Linux Users Group­Chennai

14. Other Features
• Creating snapshot using Tags.
• Creating branches of the project.
• Pserver for remote Client­Server.
• Finding out who did what (Log messages)
• Revert back to any position.
• Watching the files.
Concurrent Versioning System Indian Linux Users Group­Chennai

15. CVS and OS Support
● Relatively simple
● Available on a wide number of platforms
● Clients
– Most Linux distributions come with CLI client
– Available for Mac & Win32, CLI & GUI
● Server
– Linux CLI program is the server
– Win32 server available
Concurrent Versioning System Indian Linux Users Group­Chennai

16. ● Linux
CVS Server
– Generally comes with your distribution
● Windows
– CVSNT ­http://
cvsnt.org
● Mac OS X
– Comes with the free developer tools
Concurrent Versioning System Indian Linux Users Group­Chennai

17. GUI CVS Client
● Free
pcl­cvs
­An
Emacs Interface To CVS
Cervisia – With KDE Desktop
WinCVS ­http://
www.wincvs.org/
MacCVS ­http://
www.wincvs.org/downloads.html
TortoiseCVS ­http://
www.tortoisecvs.org/
Eclipse ­http://
eclipse.org
● Commerical
SmartCVS ­http://
smartcvs.com
Concurrent Versioning System Indian Linux Users Group­Chennai

18. CVS and Open Source
• CVS and SSH clients are used by most
developers on SourceForge.net
and freshmeat.
• Most of the projects in opensource are
maintained by CVS.
Concurrent Versioning System Indian Linux Users Group­Chennai

19. CVS Resources
● CVS Home ­http://
ximbiot.com/cvs/cvshome/
● Web Site Projects with CVS ­http://
www.durak.org/cvswebsites/howto­cvs/
● Open Source Development with CVS ­http://
cvsbook.red­bean.
com/
Concurrent Versioning System Indian Linux Users Group­Chennai

20. Advantages over CVS
SubVersion
• Atomic commits. Interrupted commit operations do not cause repository
inconsistency or corruption.
• Renamed/copied/removed files retain full revision history.
• Native support for binary files, with space­efficient
binary­diff
storage.
• Directories are versioned. Entire directory trees can be moved around
and/or copied very quickly, and retain full revision history.
• Constant time branching and tagging.
• Optimized repository accesses. This reduces unnecessary network traffic to
the repository host.
Concurrent Versioning System Indian Linux Users Group­Chennai