Bash 在后台运行时不将 Python 多处理 output 重定向到文件

Question

For the purposes of running unit tests I want to set up a local SMTP server with Python using the following command:

python -c "import smtpd, asyncore; smtpd.DebuggingServer(('127.0.0.1', 8025), None); asyncore.loop()" > test.log &

But no output gets written to the test.log file.

However, the output does get written when I run:

python -c "import smtpd, asyncore; smtpd.DebuggingServer(('127.0.0.1', 8025), None); asyncore.loop()" > test.log` or `python -c "print('TEST')" > test.log &

Does this have something to do with asyncore? Or what is going on here?

I'm on Mac OSX with Python 3.6 .

Edit: I've attempted to use the aiosmtpd module with the following command to start the server:

python -m aiosmtpd -n > test.log &

This gives the same results. So this does appear to only be an issue when dealing with multiprocessing loops

Edit 2: Simplified commands a little, removing nohup and sudo, same issue remains

Edit 3: To clarify, once I run the server I'm running the following in the interpreter to send the message:

import smtplib; server = smtplib.SMTP(host='127.0.0.1', port=8025); server.ehlo(); server.sendmail("sender@test.test", "receiver@test.test", "MESSAGE") 

Edit 4: I've even tried running the above asyncore.loop() in a file with:

python test.py > test.log &

Still no luck

Answer 1

The problem is not nohup , it's sudo . sudo must be asking for your password and then cancelling as it can't ask you while in the background, so, reordering your commands and activating the sudo background flag...

sudo -b nohup python -c "import smtpd, asyncore; smtpd.DebuggingServer(('127.0.0.1', 587), None); asyncore.loop()" > test.log

sudo -b replaces the & , because it will run python in the background.