Programming :: Passing Input To Processes As Streams (language-neutral)?

I am trying to figure out if there is a way to start a process, and while it is running, pass input to it as though it were a stream. Although the subject of this post mentions this question is "language-neutral", specifically, I am trying to do this in Common Lisp. Truly, I am looking for the principles behind the method of doing this, which seem to me as though they would be language neutral.

I have done Google searches, and found nothing relevant to my query. Without using sockets and IP communication, I would like to start a process (let's use the MySQL command-line client, for example) and then in my Common Lisp (CL) program, pass it input like so:

Code:

(format *mysql-client-instance* "SELECT * FROM some_table;")

Simply, how would I go about sending input to an active process as though it were a stream? My thinking is there has to be some way to do it - similar to the Expect superset of Tcl.