(systemcommand-string) executes a Unix, Windows, or BeOS shell
command synchronously (i.e., the call to system does not return
until the subprocess has ended), or launches a MacOS application by
its creator signature (and returns immediately). The
command-string argument is a string (of four characters for
MacOS) containing no null characters. If the command succeeds, the
return value is #t, #f otherwise. Under MacOS, if
command-string is not four characters, the
exn:application:mismatch exception is raised.
(system*command-string arg-string···) is like system,
except that command-string is a filename that is executed
directly (instead of through a shell command or through a MacOS
creator signature), and the arg-strings are the arguments.
Under Unix, Windows and BeOS, the executed file is passed the
specified string arguments (which must contain no null
characters). Under MacOS, no arguments can be supplied, otherwise the
exn:misc:unsupported exception is raised. Under Windows, the first
arg-string can be 'exact where the second
arg-string is a complete command line; see
section 15.2 in PLT MzScheme: Language Manual for details.
(processcommand-string) executes a shell command asynchronously
under Unix, Windows, and BeOS. (This procedure is not supported for
MacOS.) If the subprocess is launched successfully, the result is a
list of five values:
an input port piped from the subprocess's standard output,
an output port piped to the subprocess standard input,
the system process id of the subprocess,
an input port piped from the subprocess's standard
a procedure of one argument, either 'status,
'wait, 'interrupt, or 'kill:
'status returns the status of the subprocess as one
of 'running, 'done-ok, or
'wait blocks execution in the current thread until
the subprocess has completed.
'interrupt sends the subprocess an interrupt signal
under Unix and Mac OS X and takes no action under Windows. The result is
'kill terminates the subprocess and returns void.
Important: All three ports returned from process must
be explicitly closed with close-input-port and
(process*command-string arg-string···) is like process
under Unix for all of Unix, Windows, and BeOS, except that
command-string is a filename that is executed directly, and the
arg-strings are the arguments. (This procedure is not supported
for MacOS.) Under Windows, as for system*, the first
arg-string can be 'exact.
(process/portsoutput-port input-port error-output-port
command-string) is like process, except that output-port
is used for the process's standard output, input-port is used
for the process's standard input, and error-output-port is used
for the process's standard error. All provided ports must be
file-stream ports. Any of the ports can be #f, in which case a
system pipe is created and returned, as in process. For each
port that is provided, no pipe is created and the corresponding
returned value is #f.
(process*/portsoutput-port input-port error-output-port
command-string arg-string···) is like process*, but with the port
handling of process/ports.
9 The standard error port is placed after the process
id for compatibility with other Scheme implementations. For the same
reason, process returns a list instead of multiple values.