There are some restrictions on the names you can use for properties. A property name must start with a letter, a colon (:), or an underscore (_); after that, you can also use digits, hyphens (-), and periods (.).3
" For example, the usual line-ending token used by software on the Windows platform is a pair of ASCII control characters—a carriage return (CR) followed by a line feed (LF). Unix software, however, just uses the LF character to denote the end of a line."
"Or perhaps any files that match *.cpp should have svn:eol-style set to native, and svn:keywords set to Id. "svn:excutable
svn:igonre (不会对子目录的文件生效，故要在文件所在目录下执行 svn propset svn:ignore filename .，对于多个文件，则只能使用svn propedit svn:ignore .来操作，以免后面的覆盖前面的设置。)
$ svn propset svn:ignore -F .cvsignore .
property 'svn:ignore' set on '.'
"If that property is attached to a file (regardless of its value, which is irrelevant), Subversion will try to use filesystem-level permissions to make the file read-only—unless, of course, the user has explicitly locked the file. When a lock token is present (as a result of using svn lock), the file becomes read/write. When the lock is released, the file becomes read-only again.“
"An externals definition is a mapping of a local directory to the URL—and ideally a particular revision—of a versioned directory. "
“Keep this in mind when defining file externals. If you need the external to refer to a certain revision of a file you will not be able to modify the external. If you want to be able to modify the external, you cannot specify a revision other than the HEAD revision, which is implied if no revision is specified.“