Feature #158

- Added feature #158, regular expression support for filters and substitutions.
- Added unit tests to att.t and filter.t.
- Updated docs.

doc/man/task-faq.5

@@ -315,6 +315,26 @@ non-exact match:
 
 This will remove the second annotation - the first non-exact match.
 
+.TP
+.B Q: Does task support searching using regular expressions?
+Yes, taskwarrior supports IEEE Std 1003.2 (POSIX.2) regular expressions, but not
+by default.  You must enable this feature with the following command:
+
+    $ task config regex on
+
+Once enabled, all searches are considered regular expressions, for example:
+
+    $ task list ^the
+
+will list all tasks whose description or annotations start with "the".
+Substitutions also support regular expressions:
+
+    $ task 1 /^the/The/
+
+Note that regular expressions work in conjunction with the
+.B search.case.sensitive
+configuration setting.
+
 .TP
 .B Q: How can I help?
 There are lots of ways.  Here are some: