Can I specify directory for shell command?

Question

I use the following function to run shell commands:

(defun sh (cmd)
  #+clisp (shell cmd)
  #+ecl (si:system cmd)
  #+sbcl (sb-ext:run-program "/bin/sh" (list "-c" cmd) :input nil :output*standard-output*)
  #+clozure (ccl:run-program "/bin/sh" (list "-c" cmd) :input nil :output*standard-output*)))

For example, How to specify the current directory for command python -m CGIHTTPServer ?

Sincerely!

Answer 1

In ECL you can use EXT:CHDIR before SYSTEM, which changes both default-pathname-defaults and the value of the current directory, as understood by the operating system and C library.

BTW: If possible use (EXT:RUN-PROGRAM "command" list-of-args) instead

Answer 2

A more portable way would be to use pathnames and dynamically binding *default-pathname-defaults*, which would effectively set your current working directory. I had the same problem today. Here is a working adaptation of dot->png from Land of Lisp text by Conrad Barski, that specifies the current working directory:

(defun dot->png (filespec thunk)
  "Save DOT information generated by a thunk on a *STANDARD-OUTPUT* to a FILESPEC file. Then use FILESPEC to create a corresponding png picture of a graph."
  ;; dump DOT file first
  (let ((*default-pathname-defaults*
          (make-pathname :directory (pathname-directory (pathname filespec)))))
    ;; (format t "pwd (curr working dir): ~A~%" *default-pathname-defaults*)
    (with-open-file (*standard-output* 
                     filespec
                     :direction :output
                     :if-exists :supersede)
      (funcall thunk))
    #+sbcl
    (sb-ext:run-program "/bin/sh" 
                        (list "-c" (concatenate 'string "dot -Tpng -O " filespec))
                        :input nil
                        :output *standard-output*)
    #+clozure
    (ccl:run-program "/bin/sh" 
                     (list "-c" (concatenate 'string "dot -Tpng -O" filespec))
                     :input nil
                     :output *standard-output*)))

Posted in the hope that this could be useful to someone in a similar situation & running across this thread.