python -v writes to stderr

[deepakjoshishri]

BPO	35646
Nosy	@ericvsmith, @deepakjoshishri

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2019-01-03.07:59:30.640>
created_at = <Date 2019-01-03.07:37:42.996>
labels = ['interpreter-core', 'type-bug', 'invalid']
title = 'python -v writes to stderr'
updated_at = <Date 2019-01-03.09:21:30.916>
user = 'https://github.com/deepakjoshishri'

bugs.python.org fields:

activity = <Date 2019-01-03.09:21:30.916>
actor = 'Deepak Joshi'
assignee = 'none'
closed = True
closed_date = <Date 2019-01-03.07:59:30.640>
closer = 'eric.smith'
components = ['Interpreter Core']
creation = <Date 2019-01-03.07:37:42.996>
creator = 'Deepak Joshi'
dependencies = []
files = []
hgrepos = []
issue_num = 35646
keywords = []
message_count = 5.0
messages = ['332915', '332918', '332921', '332922', '332924']
nosy_count = 2.0
nosy_names = ['eric.smith', 'Deepak Joshi']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue35646'
versions = ['Python 2.7']

[deepakjoshishri]

Subprocess.Popen('python -v',stdout=PIPE,stderr=PIPE,Shell=True)

Prduces output in stderr instead of stdout.

For others: pip --version or git --version output is in stdout and is expected.

[ericvsmith]

-v writes to stderr, so this is the expected behavior. Although maybe this could be better documented.

See bpo-18338, where this was briefly discussed and a change was rejected.

Maybe you're looking for -V (uppercase) or --version, which do write to stdout, at least in 3.x. I'm not sure where they write in 2.7, but it's much too late to change 2.7's behavior.

I'm going to close this. If you find some of our documentation that says -v writes to stdout, then we can reopen this.

This is not a Windows specific error, so I'm modifying the nosy list.

[deepakjoshishri]

Hello,

-V and --version both write to stderr not stdout.

On Thu, 3 Jan 2019, 1:29 pm Eric V. Smith <report@bugs.python.org wrote:

Eric V. Smith <eric@trueblade.com> added the comment:

-v writes to stderr, so this is the expected behavior. Although maybe this
could be better documented.

See bpo-18338, where this was briefly discussed and a change was
rejected.

Maybe you're looking for -V (uppercase) or --version, which do write to
stdout, at least in 3.x. I'm not sure where they write in 2.7, but it's
much too late to change 2.7's behavior.

I'm going to close this. If you find some of our documentation that says
-v writes to stdout, then we can reopen this.

This is not a Windows specific error, so I'm modifying the nosy list.

----------
components: +Interpreter Core -Windows, ctypes
nosy: +eric.smith -paul.moore, steve.dower, tim.golden, zach.ware
resolution: -> not a bug
stage: -> resolved
status: open -> closed
title: Subprocess.Popen('python -v',stdout=PIPE,stderr=PIPE,Shell=True)
gives output in stderr -> python -v writes to stderr

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Python tracker <report@bugs.python.org>
<https://bugs.python.org/issue35646\>

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[ericvsmith]

That's just the way it is with 2.7.

[deepakjoshishri]

Thank you for the reply Eric.
Thought the behaviour is pretty wierd and opened the issue.

On Thu, 3 Jan 2019, 2:28 pm Eric V. Smith <report@bugs.python.org wrote:

Eric V. Smith <eric@trueblade.com> added the comment:

That's just the way it is with 2.7.

----------

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Python tracker <report@bugs.python.org>
<https://bugs.python.org/issue35646\>

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