Source%20Code%20Control%20Systems

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Source Code Control Systems
Jaap Akkerhuis jaap_at_nlnetlabs.nl
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SCCS

• Why
• How
• RCS
• CVS
• More and more

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Why Version Control

• Software Engineering
• Auditing capabilaties
• Change tracking
• Undo mistakes

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Method

• Archive (per file)
• Deltas between versions
• Delta's upon a complete version (SCCS)
• Last version complete (RCS), delta's with
  previous
• Branching, merging
• for software Engineering

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RCS intro

• Archive with extension ,v
• In sub directory RCS (if exists)
• Commands asks
• descriptive text
• comments for changes

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RCS ci co

• CI Checks a file in an archive
• removes file
• first time aks description
• CO Checks a file out an archive
• file mode Read Only
• CO -l
• check out and locks file (RW)
• CI -u
• Updates archive
• leaves file RO

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Combined actions

• ci -l
• ci -u co -l
• rcsdiff -v1.1 -v1.9
• compares version
• co -v1.1 gt 1 co -v1.9 gt 9 diff 1 9 rm 1 9

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Auditing

• Comments in Archive
• rlog pokes in archive
• RCS keywords in binary
• Log
• TLD IN TXT "tld zone version Log
• Ident for binaries
• Locks changes by other users

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CVS

• Based on RCS
• Shell scripts by Dick Grune
• Optimistic concurrency model
• users seldom hack the same concurrently
• Remote access
• Keeps removed files in attic
• allows going back in time

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CVS repository

• Central archive for project
• Check out a whole project
• cvs checkout
• make changes
• commit changes
• merges files and changes
• notifies for conflicting merges

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Further googling

• www.cvshome.org
• subversion
• tons of commercial software

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Questions ???