diff --git a/mas-cli/Commands/Install.swift b/mas-cli/Commands/Install.swift
index e2cd33b2e..1393b018e 100644
--- a/mas-cli/Commands/Install.swift
+++ b/mas-cli/Commands/Install.swift
@@ -29,6 +29,6 @@ struct InstallOptions: OptionsType {
     
     static func evaluate(m: CommandMode) -> Result<InstallOptions, CommandantError<MASError>> {
         return create
-            <*> m <| Option(key: "", defaultValue: nil, usage: "the app ID to install")
+            <*> m <| Argument(usage: "the app ID to install")
     }
 }
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