Concurrent Versions System

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ConcurrentVersionsSystem

• Presented by
• Zach Crisman
• Melissa Garcia
• 3 Feb 2003

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What is a Versioning System?

• Record the history of files
• Share code within a group
• Have multiple people edit the same files
• Merge changes from different people
• Go back in time

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The Dark Ages

• Saving every version of every file you have ever
  created.
• Saving current state of project every so often
• This would however waste an enormous amount of
  disk space.
• People would have to communicate to make sure
  only one person was editing at a time.

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The Good Old Days They Were Terrible
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CVS in Action
Demo
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Using CVS Command Line
Environment Variables CVSROOT CVS repository CVS_RSHshell EDITOR Basic
Commands cvs co cvs update
files cvs commit files cvs add files
See CVS Quick Referencehttp//www.cvshome.org/
docs/manual/cvs_17.html - SEC153
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Using CVS WinCVS
Where you can get it The O\nt\iuns directory
http//www.wincvs.org/download.html Basic
Commands Cvs Admin-Checkout module Cvs
Files-Update files Cvs Files-Commit files
Cvs Files-Add files
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SSH WinCVS

• Set HOME and PATH to where SSH is located
• Configure WinCVS to use SSH
• in WinCVS Preferences
• General - CVSROOT username_at_cvs-server-host/pat
  h/to/cvsroot
• General - Authentication SSH server
• WinCvs - HOME C\Program Files\SSH

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Understand the Output
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Public Keys

• On local
• ssh-keygen2
• Will prompt for passphrase
• Creates a .ssh2 directory in HOME directory with
  the key saved to id_dsa_1024_a.pub
• Create a identification file in the /.ssh2
  directory
• echo "IdKey id_dsa_1024_a" identification
• On remote island
• Copy public key (id_dsa_1024_a.pub) to the
  /.ssh2 directory
• Create an authorization file in the /.ssh2
  directory
• Add Key id_dsa_1024_a.pub to authorization (to
  direct the SSH server to use id_dsa_1024_a.pub as
  a valid public key when authorizing your login)

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Creating A Repository

• Check disk space requirements, etc
• Set up and empty repository
• cvs d /usr/local/cvsroot init
• Or remotely
• extuserpassword_at_hostnameport/path/to/
  repository

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What did that mean?
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Remote Repositories
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Time Travel
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Parallel Universes
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Resources

• PuTTY Homepage - http//www.chiark.greenend.org.uk
  /sgtatham/putty/
• CVS Homepage - http//www.cvshome.org/
• Cygwin - http//www.cygwin.com/
• CVS Primer - http//www.cs.washington.edu/orgs/acm
  /tutorials/dev-in-unix/cvs.html
• WinCVS http//www.wincvs.org/