mdls: add page (#4618)

pages/osx/mdls.md

@@ -0,0 +1,11 @@
+# mdls
+
+> Display the metadata attributes for a file.
+
+- Display the list of metadata attributes for file:
+
+`mdls {{path/to/file}}`
+
+- Display a specific metadata attribute:
+
+`mdls -name {{attribute}} {{path/to/file}}`