Version Control

• Each developer uses cvs checkout to create her own copy of the source tree from the CVS repository. The command can operate on a directory tree, a single file or a module; a module groups several files or directories into one entity which can be operated on as a unit. One defines modules by editing the `modules' file.
• The developer modifies, compiles and tests the code in her copy of the source tree (called a working directory) with whatever editors and tools she chooses -- Emacs, make, etags, etc. She uses cvs add and cvs remove to add and remove files.
• When the changes are complete, the developer uses cvs commit to merge her changes back into the repository. This makes her changes available to other developers.
• At any point, the developer may use cvs update to merge changes committed by others into her working directory. If there are uncommitted changes to files in her working directory, CVS prints a message and attempts to merge the changes from the repository with her changes in the working directory. If the merge fails, CVS indicates a conflict which she resolves manually with a text editor.
• The developer can show the differences between two revisions with cvs diff; show the log of changes to a particular file with cvs log; show the history of each line of a file with cvs annotate; and show who has used cvs checkout, cvs tag, and several other CVS commands, using cvs history.
• CVS supports watches, allowing developers to request notification when someone begins editing a file or obtain a list of developers currently working on a file.
• The user can record the state of the repository at a particular point with the cvs tag command and use that tag as an argument to most CVS commands, for example to retrieve the files as of the tagged point.
• The developer can create a new development branch with cvs tag -b, and manipulate branches with cvs update -r and cvs checkout -r. Subsequent operations in that working directory apply to that branch. To return to the main branch, the developer can use cvs update -A. The cvs update -j command merges changes made on another branch into the working directory.
• The existence or nonexistence of a file is itself version controlled so that files can exist on some but not all branches and users can reproduce the state of the files at any given point in time.
• The developer can mark a file as binary, which prohibits merging and line terminator conversions, using cvs admin -kb.