diff --git a/commands/compare.go b/commands/compare.go
index 11c07753da1f712201d69cf0396460fe128a536e..97e476c70ce4246a2dde1237372db7a52f49b671 100644
--- a/commands/compare.go
+++ b/commands/compare.go
@@ -12,13 +12,16 @@ import (
 
 var cmdCompare = &Command{
 	Run:   compare,
-	Usage: "compare [-u] [<USER>] [[<START>...]<END>]",
+	Usage: "compare [-u] [-b <BASE>] [<USER>] [[<START>...]<END>]",
 	Long: `Open a GitHub compare page in a web browser.
 
 ## Options:
 	-u
 		Print the URL instead of opening it.
 
+	-b <BASE>
+		Base branch to compare.
+
 	[<START>...]<END>
 		Branch names, tag names, or commit SHAs specifying the range to compare.
 		<END> defaults to the current branch name.
diff --git a/commands/help.go b/commands/help.go
index 369776967cab59fb35ca451596201f715e2778c2..dbe420fb278c9f08febb02a107530c59f9adf731 100644
--- a/commands/help.go
+++ b/commands/help.go
@@ -174,4 +174,5 @@ These GitHub commands are provided by hub:
    pr             Work with pull requests
    pull-request   Open a pull request on GitHub
    release        List or create releases
+   sync           Fetch git objects from upstream and update branches
 `