Update cheatsheets

tldr/i3-msg

@@ -0,0 +1,22 @@
+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# i3-msg
+
+> Send messages to a running instance of i3 using IPC.
+> See <https://i3wm.org/docs/userguide.html#list_of_commands> for available commands.
+> More information: <https://manned.org/i3-msg>.
+
+- Run an i3 command:
+
+`i3-msg {{command}}`
+
+- Print a list of workspaces in JSON:
+
+`i3-msg -t get_workspaces`
+
+- Print a layout tree of all open windows, containers, outputs, and workspaces in JSON:
+
+`i3-msg -t get_tree`