Uses bash+awk+find+XDG_DATA_DIRS to launch an application by searching the first x-desktop that starts with the argument (you can use wildcards, remember to escape them)

xdg-launch.sh

#!/usr/bin/env bash
set -euo pipefail
LAUNCH_SEARCHING="$1"
exec $(awk '/^Exec=/{sub(/^Exec=/, ""); print $1}' $(echo -n "$XDG_DATA_DIRS" |\
  xargs -d ':' -ri \
  find -H '{}/applications/' -iname "${LAUNCH_SEARCHING}*.desktop" 2>/dev/null |\
  head -n 1))