Specifying Oracle Service Name in UNIX Profile Is there any way we can specify Oracle Service Name in UNIX Profile?

I know that there is an environment variable ORACLE_SID for specifying SID in the Profile,

But how about service name? If there is, then can we remove ORACLE_SID once we set the Service Name in the Profile?
Use the TWO_TASK variable and set it to [server]/[service]

export TWO_TASK=server.example.com/mydb

This will override ORACLE_SID and make a sqlnet connection to the DB.