--- a/node_modules/matrix-react-sdk/src/SlashCommands.tsx
+++ b/node_modules/matrix-react-sdk/src/SlashCommands.tsx
@@ -68,6 +68,29 @@

 export const Commands = [
     new Command({
+        command: "greentext",
+        args: "<message>",
+        description: _td("4chan-like greentext arrows"),
+        runFn: function(cli, roomId, threadId, args) {
+            const texts = args.split(/\n{2,}(.+|\n+)/g);
+            const greentext = texts[0];
+            const normalText = texts[1] || "";
+
+            let plainGreentext = greentext.replace(/^/g, ">");
+            plainGreentext = plainGreentext.replace(/(?:\r\n|\r|\n)+/g, "\n>");
+
+            let htmlGreentext = greentext.replace(/^/g, "&gt;");
+            htmlGreentext = htmlGreentext.replace(/(?:\r\n|\r|\n)+/g, "<br />&gt;");
+
+            return success(ContentHelpers.makeHtmlMessage(
+                plainGreentext + "\n" + normalText,
+                `<font color="#789922">${htmlGreentext}</font><br/>${normalText}`,
+            ));
+        },
+        category: CommandCategories.messages,
+    }),
+
+    new Command({
         command: "spoiler",
         args: "<message>",
         description: _td("slash_command|spoiler"),