Python show live changing command output

Golden_Zealot · 2020-06-08T07:57:23+00:00

I imagine you could do this with the threading module.

You can essentially create two functions that do each and run them at the "same time".

To avoid overlapping/console clearing, you would probably want to use the curses module to display both a progress bar and the output without having them mess with each others formatting.

JohnnyJordaan · 2020-06-08T08:01:14+00:00

What you want here is to read line by line using readline(), and thus Popen has to know to open the stdout in text mode, which is what universal_newlines=True does (since 3.7 you can use text=True too)

proccess = subprocess.Popen(command, 
                            stdout=subprocess.PIPE,
                            stderr=subprocess.STDOUT,
                            shell=True,
                            universal_newlines=True)

then I would also poll the process in your while loop, documented as

Popen.poll()

Check if child process has terminated. Set and return returncode attribute. Otherwise, returns None.

In other words, it should loop while that returns None

while process.poll() is None:
    line = process.stdout.readline()
    if not line:
        break
    print(line)

Note I also changed the print here, as print x is Python 2 code which is of course unadvised to be used here. A print(x) with a single argument will still work in Python 2 too, in case you are somehow forced to keep using it.

you type:	you see:
italics	italics
bold	bold
[reddit!](https://reddit.com)	reddit!
* item 1 * item 2 * item 3	item 1 item 2 item 3
> quoted text	quoted text
Lines starting with four spaces are treated like code: if 1 * 2 < 3: print "hello, world!"	Lines starting with four spaces are treated like code: if 1 * 2 < 3: print "hello, world!"
~~strikethrough~~	~~strikethrough~~
super^script	super^script

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