Add subcmd virtmon (WIP)

sdata/subcmd-virtmon/0.run.sh

@@ -0,0 +1,13 @@
+# This script is meant to be sourced.
+# It's not for directly running.
+
+# shellcheck shell=bash
+
+readarray -t vmon < <(hyprctl -j monitors all | jq -r '.[] | select(.name | test("^HEADLESS-")) | .name')
+
+if [ "${#vmon[@]}" -gt 0 ]; then
+  printf '%s\n' "${vmon[@]}"
+else
+  echo "no headless monitors found" >&2
+  exit 1
+fi