Tracking versions with SCCS

More on get

The command

   $ get s.lang

retrieves the latest version of the file s.lang, now 1.2. SCCS does this by starting with the original version of the file and applying the delta you made. If you use the get command now, any of the following will retrieve version 1.2:

   $ get s.lang
   $ get -r1 s.lang
   $ get -r1.2 s.lang

The numbers following -r are SIDs. When you omit the level number of the SID (as in get -r1 s.lang), the default is the highest level number that exists within the specified release. Thus, the second command requests the retrieval of the latest version in release 1, namely 1.2. The third command requests the retrieval of a particular version, in this case also 1.2.

Whenever a major change is made to a file, you may want to signify it by changing the release number, the first number of the SID. This, too, is done with the get command:

   $ get -e -r2 s.lang

Because release 2 does not exist, get retrieves the latest version before release 2. get also interprets this as a request to change the release number of the new delta to 2, thereby naming it 2.1 rather than 1.3. The output is

   1.2
   new delta 2.1
   7 lines

which means version 1.2 has been retrieved, and 2.1 is the version the delta command will create. If the file is now edited -- for example, by deleting COBOL from the list of languages -- and delta is executed

   $ delta s.lang
   comments? deleted cobol from list of languages

you will see by delta's output that version 2.1 is indeed created:

   2.1
   0 inserted
   1 deleted
   6 unchanged

Deltas can now be created in release 2 (deltas 2.2, 2.3, etc.), or another new release can be created in a similar manner. A delta can still be made to the ``old'' release 1. This is explained in ``Delta numbering''.