In a Promotion process,
create a "Parameter String" : MY_PROMOTION_PARAMTER_STRING

In a Send Build artefact over SSH
Add a Exec command script :
echo '--- SSH Script'
echo $MY_PROMOTION_PARAMTER_STRING

And to compare to wanted result
In a Shell Script
echo '--- Local Script'
echo $MY_PROMOTION_PARAMTER_STRING

During promotion the value is not evaluated.