<book>
<title>User service daemon and client specification
<author>Ian Jackson <email>ian@davenant.greenend.org.uk
-<version>0.61.3</version>
+<version>0.64.1</version>
<abstract>
This is a specification for a Unix system facility to allow one
<p>
A translation will be applied to values before they are used to
-construct a filename, so that the lookup cannot access dotfiles or
-files in other directories: values starting with full stops will have
-a colon prepended (making <tt/:./), colons will be doubled, and each
-slash will be replaced with a colon followed by a hyphen <tt>:-</>. A
-parameter value which is the empty string will be replaced with
+construct a filename, so that the lookup cannot access dotfiles,
+backup files, files in other directories and the like: each slash will
+be replaced with a colon followed by a hyphen <tt>:-</>, and all
+characters which are not lowercase alphanumerics, hyphens or
+underscores will have a colon prepended (so that colons are doubled).
+A parameter value which is the empty string will be replaced with
<tt/:empty/ (note that this is different from a parameter not having
any values).