diff --git a/README.md b/README.md
index d3d5686..4629484 100644
--- a/README.md
+++ b/README.md
@@ -63,8 +63,12 @@ recreated. The `skeleton` and `predicate` arguments cannot be used together.
 ### Tar.extract
 
 ```jl
-extract([ predicate, ] tarball, [ dir ];
-        [ skeleton, ] [ copy_symlinks ]) -> dir
+extract(
+    [ predicate, ] tarball, [ dir ];
+    [ skeleton = <none>, ]
+    [ copy_symlinks = <auto>, ]
+    [ set_permissions = true, ]
+) -> dir
 ```
 * `predicate       :: Header --> Bool`
 * `tarball         :: Union{AbstractString, AbstractCmd, IO}`
diff --git a/src/Tar.jl b/src/Tar.jl
index 3ee7013..a580019 100644
--- a/src/Tar.jl
+++ b/src/Tar.jl
@@ -166,9 +166,12 @@ function list(
 end
 
 """
-    extract([ predicate, ] tarball, [ dir ];
-            [ skeleton, ] [ copy_symlinks ],
-            [ set_permissions ]) -> dir
+    extract(
+        [ predicate, ] tarball, [ dir ];
+        [ skeleton = <none>, ]
+        [ copy_symlinks = <auto>, ]
+        [ set_permissions = true, ]
+    ) -> dir
 
         predicate       :: Header --> Bool
         tarball         :: Union{AbstractString, AbstractCmd, IO}