Path: csiph.com!fu-berlin.de!uni-berlin.de!not-for-mail From: Tim Johnson Newsgroups: comp.lang.python Subject: Re: Using subprocess to capture a progress line Date: Wed, 11 Nov 2015 07:16:57 -0900 Organization: AkWebsoft Lines: 41 Message-ID: References: <20151110224756.GA1944@mail.akwebsoft.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Trace: news.uni-berlin.de 5YCu1COBYW1X+zdBes59NgQXYThnLp7MoqjOcRkM1unA== Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.014 X-Spam-Evidence: '*H*': 0.97; '*S*': 0.00; 'messages.': 0.04; 'mess': 0.09; '\xe2\x80\x94': 0.09; 'python': 0.10; 'carriage': 0.16; 'goal,': 0.16; 'i.e.,': 0.16; 'naq': 0.16; 'overwriting': 0.16; 'received:io': 0.16; 'received:psf.io': 0.16; 'repr()': 0.16; 'subprocess': 0.16; 'worst': 0.16; 'wrote:': 0.16; 'library,': 0.18; 'module,': 0.18; '2015': 0.20; 'developers.': 0.22; 'this:': 0.23; 'cheers': 0.24; 'implemented': 0.24; 'tim': 0.24; 'header :In-Reply-To:1': 0.24; 'header': 0.24; 'header:User-Agent:1': 0.26; 'chris': 0.26; 'figure': 0.27; 'module.': 0.27; 'reply-to': 0.29; 'sensible': 0.29; 'character': 0.29; 'read,': 0.29; 'print': 0.30; 'skip:[ 10': 0.31; 'ubuntu': 0.33; 'file': 0.34; 'list': 0.34; 'something': 0.35; 'problem.': 0.35; 'but': 0.36; 'should': 0.36; 'there': 0.36; '(3)': 0.36; 'to:addr:python-list': 0.36; 'subject:: ': 0.37; 'method': 0.37; 'setting': 0.37; 'thanks': 0.37; '(2)': 0.37; 'johnson': 0.37; 'things': 0.38; '(1)': 0.38; 'thank': 0.38; 'end': 0.39; 'means': 0.39; 'to:addr:python.org': 0.40; 'some': 0.40; 'your': 0.60; 'further': 0.62; 'fact,': 0.67; 'reply': 0.68; '8bit%:21': 0.70; '100%': 0.72; 'i\xe2\x80\x99ll': 0.84; 'subject:Using': 0.84; 'glad': 0.87; 'ps.': 0.91 Mail-Followup-To: python-list@python.org Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.20+ Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Xref: csiph.com comp.lang.python:98645 * Chris Warrick [151111 00:55]: > On 10 November 2015 at 23:47, Tim Johnson wrote: > > Using python 2.7.6 on ubuntu 14.04 <..> > There is no \n character at the end — which means that > p.stdout.readline() cannot return. In fact, if you printed repr() of > the line you read, you would get this: > > b'\r[download] 54.9% of 2.73MiB at 26.73KiB/s ETA 00:47\r[download] > 55.0% of 2.73MiB at 79.33KiB/s ETA 00:15\r…snip…\r[download] 100% of > 2.73MiB in 00:01\n' > > The download line is implemented using \r, which is the carriage > return character (return to the first character), and then by > overwriting characters that were already printed. > > The solution? There are numerous. I’ll help you by obscuring the worst one. > > (1) [recommended] figure out how to make youtube_dl work as a library, > read its main file to figure out the problem. Don’t mess with > subprocess. Was my first goal, had some problems, but I have solved them in part by finding the good documentation of the developers. I.E., the subprocess method _is_ going away and I will be using the youtube_dl module. > (2) [don’t do it] do you need to intercept the lines? If you don’t set > stderr= and stdout=, things will print just fine. Got to try that before using the module, just for edification. > (3) [DON’T DO IT] .ernq() punenpgre ol punenpgre naq znxr n zrff. > > PS. Thank you for setting a sensible Reply-To header on your messages. > Which is something the list should be doing. LOL! Glad to help :) Thanks for the reply and the further education. Cheers -- Tim http://www.akwebsoft.com, http://www.tj49.com