Redirecting stdin/stdout/setderr and os.execv

[Jason Orendorff]

Richard Philips wrote:
> I understand the solution, and it solves the problem on UNIX.
> But os.fork() is not usable on win32.
>
> I would like a solution which work both on UNIX and windows !

# Use spawnv() instead of fork()/execv().
# This works for me on Windows 2000.

import os, sys

STDIN_FILENO = 0
STDOUT_FILENO = 1
STDERR_FILENO = 2

def run(program, argv, outfile):
    orig_stdout = os.dup(STDOUT_FILENO)
    try:
        new_stdout = os.open(outfile, os.O_WRONLY | os.O_CREAT | os.O_TRUNC)
        try:
            os.dup2(new_stdout, STDOUT_FILENO)
            try:
                return os.spawnv(os.P_WAIT, program, argv)
            finally:
                os.dup2(orig_stdout, STDOUT_FILENO)
        finally:
            os.close(new_stdout)
    finally:
        os.close(orig_stdout)


status = run("C:\\programs\\cygwin\\bin\\ls.exe",
             ["ls", "-1"],
             "output.txt")
print "ls completed with status:", status


## Jason Orendorff    http://www.jorendorff.com/