Unix Processes

In order to launch unix commands from EusLisp, use the unix:system function. Piped-fork creates a subprocess whose standard input and standard output are connected to EusLisp's bidirectional stream through pipes. Piped-fork returns the stream. Following is a function to count the number of lines contained in a file by using "wc".

(defun count-lines (file) (read (piped-fork "wc" file)))

The next example creates eus process on another workstation identified by "etlic0" and provides a port for distributed computation.

(setq ic0eus (piped-fork "rsh" "etlic0" "eus"))
(format ic0eus "(list 1 2 3)~%")
(read ic0eus) --> (1 2 3)

For source code editing, you can call ez from the EusLisp. The screen editor ez communicates with EusLisp through message-queues. If you have an ez process already running in parallel with the EusLisp, ez restarts ez and it gains the terminal control. By issuing esc-P or esc-M commands in ez, texts are sent back and evaluated by EusLisp. This is useful for the debugging since entire file does not need to be loaded when you add a little modification to the file. Similar function is available on emacs by M-X run-lisp command.

  cd &optional (dir (unix:getenv "HOME")) [function]

• changes the current working directory.

  ez &optional key [function]

• enters display editor ez, and reads Lisp forms from it, and evaluates them.

  piped-fork &optional (exec) &rest args [function]

• forks a process, and makes a two-way stream between EusLisp and the subprocess.

  rusage [function]

• prints resource usage of this process.