@@ -43,7 +43,24 @@ };
     functions = {
       ds = "du -hd1 $argv[1] | sort -h";
       last_history_item = "echo $history[1]";
-    };
+    } // (lib.attrsets.optionalAttrs pkgs.stdenv.isLinux {
+      open = ''
+        argparse h/help a/application -- $argv
+        or return
+
+        if set -ql _flag_help
+           echo "open [-h|--help] [-a application] [arguments...]"
+           return 1
+        end
+
+        if set -ql _flag_application
+           # TODO: support reverse-domain- named files (e.g. org.kde.kate.desktop)
+           ${pkgs.gtk3}/bin/gtk-launch $argv[1]
+        else
+          xdg-open $argv
+        end
+      '';
+    });
   };
   xdg.configFile."fish/completions" = {
     recursive = true;