Issue #16624: `subprocess.check_output` now accepts an `input` argument,
allowing the subprocess's stdin to be provided as a (byte) string.
Patch by Zack Weinberg.
diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index f69b42a..78907e0 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -175,6 +175,9 @@
>>> output = subprocess.check_output(["ls", "-l", "/dev/null"])
+ There is an additional optional argument, "input", allowing you to
+ pass a string to the subprocess's stdin. If you use this argument
+ you may not also use the Popen constructor's "stdin" argument.
Exceptions
----------
@@ -563,14 +566,31 @@
... stderr=STDOUT)
b'ls: non_existent_file: No such file or directory\n'
+ There is an additional optional argument, "input", allowing you to
+ pass a string to the subprocess's stdin. If you use this argument
+ you may not also use the Popen constructor's "stdin" argument, as
+ it too will be used internally. Example:
+
+ >>> check_output(["sed", "-e", "s/foo/bar/"],
+ ... input=b"when in the course of fooman events\n")
+ b'when in the course of barman events\n'
+
If universal_newlines=True is passed, the return value will be a
string rather than bytes.
"""
if 'stdout' in kwargs:
raise ValueError('stdout argument not allowed, it will be overridden.')
+ if 'input' in kwargs:
+ if 'stdin' in kwargs:
+ raise ValueError('stdin and input arguments may not both be used.')
+ inputdata = kwargs['input']
+ del kwargs['input']
+ kwargs['stdin'] = PIPE
+ else:
+ inputdata = None
with Popen(*popenargs, stdout=PIPE, **kwargs) as process:
try:
- output, unused_err = process.communicate(timeout=timeout)
+ output, unused_err = process.communicate(inputdata, timeout=timeout)
except TimeoutExpired:
process.kill()
output, unused_err = process.communicate()