How do you combine the two language.
Actually neither one is a computer language. I think you probably mean SQLPLUS (Oracle inquiry) and UNIX shell.
Simple example using a UNIX shell here document to call a sqlplus command
for a pretend user, passwd, and Oracle instance. You have to be able to execute the sqlplus command and have a valid oracle account before this will work:
sqlplus -s user/passwd@instance << -EOF
set head off
select field1 from mytable;
exit
EOF