pkgutil: add page (osx) (#3755)

pages/osx/pkgutil.md

@@ -0,0 +1,15 @@
+# pkgutil
+
+> Query and manipulate Mac OS X Installer packages and receipts.
+
+- List package IDs for all installed packages:
+
+`pkgutil --pkgs`
+
+- Verify cryptographic signatures of a package file:
+
+`pkgutil --check-signature {{filename.pkg}}`
+
+- List all the files for an installed package given its ID:
+
+`pkgutil --files {{com.microsoft.Word}}`