.. availability:: Unix.
-.. function:: popen(cmd, mode='r', buffering=-1, encoding=None)
+.. function:: popen(cmd, mode='r', buffering=-1)
Open a pipe to or from command *cmd*.
The return value is an open file object
connected to the pipe, which can be read or written depending on whether *mode*
is ``'r'`` (default) or ``'w'``.
- The *buffering* and *encoding* arguments have the same meaning as
+ The *buffering* argument have the same meaning as
the corresponding argument to the built-in :func:`open` function. The
returned file object reads or writes text strings rather than bytes.
documentation for more powerful ways to manage and communicate with
subprocesses.
- .. versionchanged:: 3.11
- Added the *encoding* parameter.
+ .. note::
+ The :ref:`Python UTF-8 Mode <utf8-mode>` affects encodings used
+ for *cmd* and pipe contents.
+
+ :func:`popen` is a simple wrapper around :class:`subprocess.Popen`.
+ Use :class:`subprocess.Popen` or :func:`subprocess.run` to
+ control options like encodings.
.. function:: posix_spawn(path, argv, env, *, file_actions=None, \
# command in a shell can't be supported.
if sys.platform != 'vxworks':
# Supply os.popen()
- def popen(cmd, mode="r", buffering=-1, encoding=None):
+ def popen(cmd, mode="r", buffering=-1):
if not isinstance(cmd, str):
raise TypeError("invalid cmd type (%s, expected string)" % type(cmd))
if mode not in ("r", "w"):
raise ValueError("invalid mode %r" % mode)
if buffering == 0 or buffering is None:
raise ValueError("popen() does not support unbuffered streams")
- import subprocess, io
- encoding = io.text_encoding(encoding)
+ import subprocess
if mode == "r":
proc = subprocess.Popen(cmd,
shell=True, text=True,