Version Control with Subversion, 2nd Edition

Using External Editors

The most obvious way to get data into Subversion is through the addition of files to version control, committing changes to those files, and so on. But other pieces of information besides merely versioned file data live in your Subversion repository. Some of these bits of information—commit log messages, lock comments, and some property values—tend to be textual in nature and are provided explicitly by users. Most of this information can be provided to the Subversion command-line client using the --message (-m) and --file (-F) options with the appropriate subcommands.

Each of these options has its pros and cons. For example, when performing a commit, --file (-F) works well if you’ve already prepared a text file that holds your commit log message. If you didn’t, though, you can use --message (-m) to provide a log message on the command line. Unfortunately, it can be tricky to compose anything more than a simple one-line message on the command line. Users want more flexibility—multiline, free-form log message editing on demand.

Subversion supports this by allowing you to specify an external text editor that it will launch as necessary to give you a more powerful input mechanism for this textual metadata. There are several ways to tell Subversion which editor you’d like use. Subversion checks the following things, in the order specified, when it wants to launch such an editor:

1. --editor-cmd command-line option

2. SVN_EDITOR environment variable

3. editor-cmd runtime configuration ...