diff --git a/mercurial/commands.py b/mercurial/commands.py
--- a/mercurial/commands.py
+++ b/mercurial/commands.py
@@ -4577,6 +4577,12 @@
             _(b'BRANCH'),
         ),
         (
+            b'B',
+            b'bookmark',
+            [],
+            _(b"show changesets within the given bookmark"),
+            _(b'BOOKMARK')),
+        (
             b'P',
             b'prune',
             [],
diff --git a/tests/test-completion.t b/tests/test-completion.t
--- a/tests/test-completion.t
+++ b/tests/test-completion.t
@@ -342,7 +342,7 @@
   incoming: force, newest-first, bundle, rev, bookmarks, branch, patch, git, limit, no-merges, stat, graph, style, template, ssh, remotecmd, insecure, subrepos
   init: ssh, remotecmd, insecure
   locate: rev, print0, fullpath, include, exclude
-  log: follow, follow-first, date, copies, keyword, rev, line-range, removed, only-merges, user, only-branch, branch, prune, patch, git, limit, no-merges, stat, graph, style, template, include, exclude
+  log: follow, follow-first, date, copies, keyword, rev, line-range, removed, only-merges, user, only-branch, branch, bookmark, prune, patch, git, limit, no-merges, stat, graph, style, template, include, exclude
   manifest: rev, all, template
   merge: force, rev, preview, abort, tool
   outgoing: force, rev, newest-first, bookmarks, branch, patch, git, limit, no-merges, stat, graph, style, template, ssh, remotecmd, insecure, subrepos