apparently oracle removed tnsping from the instant client 220.127.116.11.
this very handy command to do some troubleshooting is crucial in our environment so we tried to add it from a full blown oracle client installation.
in order to add tnsping to the instant_client you must copy the tnsping command to the bin directory of the instant client.
however you also need to copy
$ORACLE_HOME/network/message directory to the instant client directory in the network subdir
also if you want to make use of ldap you need to copy the
$ORACLE_HOME/ldap directory to you instant client directory.
and $ORACLE_HOME/lib directory to your instant client directory.