Hey @gmark,
I expect the easiest way is to use the Keyboard Maestro URL-scheme.
#!/usr/bin/env bash
open kmtrigger://macro=AFB1EE80-3A76-4E58-A0E8-4C742CBC5C5F
The last parameter is the UUID of the macro.
If/when you run AppleScript from Bash I recommend making it readable. One-liners may seem streamlined, but when you have to maintain them they can be very hard to read.
#!/usr/bin/env bash
read -r -d '' asCmdStr <<'EOF'
tell application "Keyboard Maestro Engine"
do script "AFB1EE80-3A76-4E58-A0E8-4C742CBC5C5F"
end tell
EOF
osascript -e "$asCmdStr"
-Chris