I had done that earlier it was showing the following text and immediately exiting the script

Dumping Koha site medica:

 

thanks to @Joubu's pointer, it made me look more closely at the dump_instance() function in the koha-dump. apparently the following line was the reason behind the script's sudden termination:

mysqlhost="$( xmlstarlet sel -t -v 'yazgfs/config/hostname' $kohaconfig )"

In the end it was the given instance's empty 'yazgfs/config/hostname' node. Filling it with 'localhost' sorted out the issue.

cheers

-Indranil