mons: add page (#3363)

pages/linux/mons.md

@@ -0,0 +1,20 @@
+# mons
+
+> A tool to quickly manage two displays.
+> More information: <https://github.com/Ventto/mons>.
+
+- Enable only the primary monitor:
+
+`mons -o`
+
+- Enable only the secondary monitor:
+
+`mons -s`
+
+- Duplicate the primary monitor onto the secondary monitor, using the resolution of the primary monitor:
+
+`mons -d`
+
+- Mirror the primary monitor onto the secondary monitor, using the resolution of the secondary monitor:
+
+`mons -m`