mercurial/help/templates.txt

--- a/mercurial/help/templates.txt	Thu Jun 12 17:45:41 2014 -0700
+++ b/mercurial/help/templates.txt	Thu Jun 12 17:53:37 2014 -0700
@@ -66,6 +66,8 @@
 
 - shortest(node)
 
+- startswith(string, text)
+
 - strip(text[, chars])
 
 - sub(pat, repl, expr)
@@ -124,3 +126,7 @@
 - Mark the working copy parent with '@'::
 
    $ hg log --template "{ifcontains(rev, revset('.'), '@')}\n"
+
+- Show only commit descriptions that start with "template"::
+
+   $ hg log --template "{startswith(\"template\", firstline(desc))}\n"