Document that on Unix, the 'cmd' argument to the os.popen2/3/4 and

popen2.popen2/3/4 functions can be a sequence. All texts are a variation on the
following:

On \UNIX, \var{cmd} may be a sequence, in which case arguments will be passed
directly to the program without shell intervention (as with
\function{os.spawnv()}). If \var{cmd} is a string it will be passed to the shell
(as with \function{os.system()}).

1 files changed, 44 insertions, 22 deletions

diff --git a/Lib/popen2.py b/Lib/popen2.py
index acba60258b..3f84bf9e85 100644
--- a/Lib/popen2.py
+++ b/Lib/popen2.py
@@ -30,10 +30,14 @@ class Popen3:
 
     def __init__(self, cmd, capturestderr=False, bufsize=-1):
         """The parameter 'cmd' is the shell command to execute in a
-        sub-process.  The 'capturestderr' flag, if true, specifies that
-        the object should capture standard error output of the child process.
-        The default is false.  If the 'bufsize' parameter is specified, it
-        specifies the size of the I/O buffers to/from the child process."""
+        sub-process.  On UNIX, 'cmd' may be a sequence, in which case arguments
+        will be passed directly to the program without shell intervention (as
+        with os.spawnv()).  If 'cmd' is a string it will be passed to the shell
+        (as with os.system()).   The 'capturestderr' flag, if true, specifies
+        that the object should capture standard error output of the child
+        process.  The default is false.  If the 'bufsize' parameter is
+        specified, it specifies the size of the I/O buffers to/from the child
+        process."""
         _cleanup()
         p2cread, p2cwrite = os.pipe()
         c2pread, c2pwrite = os.pipe()
@@ -120,44 +124,62 @@ if sys.platform[:3] == "win" or sys.platform == "os2emx":
     del Popen3, Popen4
 
     def popen2(cmd, bufsize=-1, mode='t'):
-        """Execute the shell command 'cmd' in a sub-process.  If 'bufsize' is
-        specified, it sets the buffer size for the I/O pipes.  The file objects
-        (child_stdout, child_stdin) are returned."""
+        """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may
+        be a sequence, in which case arguments will be passed directly to the
+        program without shell intervention (as with os.spawnv()). If 'cmd' is a
+        string it will be passed to the shell (as with os.system()). If
+        'bufsize' is specified, it sets the buffer size for the I/O pipes. The
+        file objects (child_stdout, child_stdin) are returned."""
         w, r = os.popen2(cmd, mode, bufsize)
         return r, w
 
     def popen3(cmd, bufsize=-1, mode='t'):
-        """Execute the shell command 'cmd' in a sub-process.  If 'bufsize' is
-        specified, it sets the buffer size for the I/O pipes.  The file objects
-        (child_stdout, child_stdin, child_stderr) are returned."""
+        """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may
+        be a sequence, in which case arguments will be passed directly to the
+        program without shell intervention (as with os.spawnv()). If 'cmd' is a
+        string it will be passed to the shell (as with os.system()). If
+        'bufsize' is specified, it sets the buffer size for the I/O pipes. The
+        file objects (child_stdout, child_stdin, child_stderr) are returned."""
         w, r, e = os.popen3(cmd, mode, bufsize)
         return r, w, e
 
     def popen4(cmd, bufsize=-1, mode='t'):
-        """Execute the shell command 'cmd' in a sub-process.  If 'bufsize' is
-        specified, it sets the buffer size for the I/O pipes.  The file objects
-        (child_stdout_stderr, child_stdin) are returned."""
+        """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may
+        be a sequence, in which case arguments will be passed directly to the
+        program without shell intervention (as with os.spawnv()). If 'cmd' is a
+        string it will be passed to the shell (as with os.system()). If
+        'bufsize' is specified, it sets the buffer size for the I/O pipes. The
+        file objects (child_stdout_stderr, child_stdin) are returned."""
         w, r = os.popen4(cmd, mode, bufsize)
         return r, w
 else:
     def popen2(cmd, bufsize=-1, mode='t'):
-        """Execute the shell command 'cmd' in a sub-process.  If 'bufsize' is
-        specified, it sets the buffer size for the I/O pipes.  The file objects
-        (child_stdout, child_stdin) are returned."""
+        """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may
+        be a sequence, in which case arguments will be passed directly to the
+        program without shell intervention (as with os.spawnv()). If 'cmd' is a
+        string it will be passed to the shell (as with os.system()). If
+        'bufsize' is specified, it sets the buffer size for the I/O pipes. The
+        file objects (child_stdout, child_stdin) are returned."""
         inst = Popen3(cmd, False, bufsize)
         return inst.fromchild, inst.tochild
 
     def popen3(cmd, bufsize=-1, mode='t'):
-        """Execute the shell command 'cmd' in a sub-process.  If 'bufsize' is
-        specified, it sets the buffer size for the I/O pipes.  The file objects
-        (child_stdout, child_stdin, child_stderr) are returned."""
+        """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may
+        be a sequence, in which case arguments will be passed directly to the
+        program without shell intervention (as with os.spawnv()). If 'cmd' is a
+        string it will be passed to the shell (as with os.system()). If
+        'bufsize' is specified, it sets the buffer size for the I/O pipes. The
+        file objects (child_stdout, child_stdin, child_stderr) are returned."""
         inst = Popen3(cmd, True, bufsize)
         return inst.fromchild, inst.tochild, inst.childerr
 
     def popen4(cmd, bufsize=-1, mode='t'):
-        """Execute the shell command 'cmd' in a sub-process.  If 'bufsize' is
-        specified, it sets the buffer size for the I/O pipes.  The file objects
-        (child_stdout_stderr, child_stdin) are returned."""
+        """Execute the shell command 'cmd' in a sub-process. On UNIX, 'cmd' may
+        be a sequence, in which case arguments will be passed directly to the
+        program without shell intervention (as with os.spawnv()). If 'cmd' is a
+        string it will be passed to the shell (as with os.system()). If
+        'bufsize' is specified, it sets the buffer size for the I/O pipes. The
+        file objects (child_stdout_stderr, child_stdin) are returned."""
         inst = Popen4(cmd, bufsize)
         return inst.fromchild, inst.tochild