Subversion is an open source version control system.
Each file or directory can have special properties associated to it.
This helps you mount another subversion repo path on a directory. e.g. if I want my “img” folder to be pulled from the URL “http://example.com/images", then you can add the external “http://example.com/images img” on a directory. The next svn update will create the “img” directory, and download the contents with the URL. If you want multiple externals you can put them on separate lines.
This is powerful but watch out for the following:
- It can be slower when doing svn updates, as 2 separate updates are made.
- Branching will get complicated.
- Some programs have an option to skip updates for directories specified by svn:externals (e.g. teamcity). If your externals are not being updated then this may be the reason.