How to "tee" (=split) output to screen and into file?

[pstein]

Assume I want to write something from inside a *.py script to screen AND into file D:\tools\python\myoutput.log

How can I achive this WITHOUT executing the same command twice?

Is there something linke a "tee" command similar to

print ("hello") | >D:\tools\üython\myoutput.log

[rob101]

I don't know that you can do that with a single command, but I would do this:

with open("file_name", mode='w', encoding='UTF8') as output:
    something = "This is what you want to write"
    print(something)
    print(something, file=output)

[Gribouillis]

You can simulate it by replacing temporarily sys.stdout with a custom file object that contains a pointer to the new file

import contextlib
import sys

class _Tee:
    def __init__(self, *files):
        self.files = files

    def write(self, s):
        for f in self.files:
            f.write(s)
        return len(s)  # not perfect

    def flush(self):
        for f in self.files:
            f.flush()


@contextlib.contextmanager
def tee(filename):
    stdout = sys.stdout
    try:
        with open(filename, 'w') as f:
            sys.stdout = _Tee(sys.stdout, f)
            yield sys.stdout
    finally:
        sys.stdout = stdout

def main():
    print('hello')
    print('bye')

if __name__ == '__main__':

    with tee('myoutput.log'):
        main()

Output:
hello
bye

[Pedroski55]

The wheel has already been invented, and so has logging!

Python has a logging module of course. Look here.

And here.

import logging
 
# Create the file
# and output every level since 'DEBUG' is used
# and remove all headers in the output
# using empty format=''
logging.basicConfig(filename='output.txt', level=logging.DEBUG, format='')
 
logging.debug('Hi')
logging.info('Hello from AskPython')
logging.warning('exit')

file_name = '/home/pedro/temp/atext1.txt'
print('\nHi', file=open(file_name, 'a'))

[Gribouillis]

The wheel has already been invented, and so has logging!

This is true of course and in general, it is probably better to log than to print. However there is a little difference: in the logging system, you emit logging 'records', there is no way to use the exact semantics of the print() function with its sep and end and flush arguments. So the print function not only outputs information, it also formats the information with lower level details. I don't know how you could plug this semantics to the logging system.

[Pedroski55]

Simple answer: the OP wanted to log to myoutput.log:

Assume I want to write something from inside a *.py script to screen AND into file D:\tools\python\myoutput.log

[Gribouillis]

Simple answer: the OP wanted to log to myoutput.log:

I understand the OP wanted to 'tee' like in the Linux command 'tee' where you just copy the output of a program to other files. I think it all depends on the context and the motivations of this. Tee has its own flexibility.