+--::
+ Do not interpret any more arguments as options.
+
+<head>...::
+ In addition to objects
+ reachable from any of our references, keep objects
+ reachable from listed <head>s.
+
+EXAMPLE
+-------
+
+To prune objects not used by your repository nor another that
+borrows from your repository via its
+`.git/objects/info/alternates`:
+
+------------
+$ git prune $(cd ../another && $(git-rev-parse --all))
+------------