如何在后台进程中将stderr和stdout重定向到/ var / log目录？

Question

With the below command ,all stderr and stdout redirect into /tmp/ss.log and it perform in background process.

python  sslocal -c /etc/shadowsocks.json  > /tmp/ss.log   2>&1 &

Now to redirect stderr and stdout into /var/log directory as following.

python  sslocal -c /etc/shadowsocks.json  > /var/log/ss.log   2>&1 &
bash: /var/log/ss.log: Permission denied  

It encounter permission problem.
I made a try with sudo tee as following.

python  sslocal -c /etc/shadowsocks.json  |sudo tee -a /var/log/ss.log   2>&1 &
python  sslocal -c /etc/shadowsocks.json  2>&1|sudo tee -a /var/log/ss.log  &
nohup python  sslocal -c /etc/shadowsocks.json  |sudo tee -a /var/log/ss.log   2>&1 &
nohup python  sslocal -c /etc/shadowsocks.json  2>&1|sudo tee -a /var/log/ss.log  &    

All of them encounter another problem,the command can't run in background process,it run as foreground process.

How to redirect stderr and stdout into /var/log directory in background process?

Answer 1

Although you try to redirect stdout / stderr using bash redirection, I may add another alternative: Redirect within your code :

import sys
sys.stdout = open(stdout.log, 'w')
sys.stderr = open(stderr.log, 'w')

You just need to execute this code during application startup and all the output ( stdout , and stderr ) will be written to the defined log files.

Answer 2

只需以root身份调用重定向：

sudo sh -c 'python  sslocal -c /etc/shadowsocks.json  > /var/log/ss.log   2>&1' &

Answer 3

sudo vi /etc/systemd/system/ss.service

[Unit]
Description=ss

[Service]
TimeoutStartSec=0
ExecStart=/bin/bash -c '/python sslocal -c /etc/ss.json > /var/log/ss.log 2>&1'

[Install]
WantedBy=multi-user.target

To start it after editing the config file.

sudo systemctl daemon-reload
sudo systemctl enable ss.service
sudo systemctl start ss.service
sudo systemctl status ss -l

1.ss run as a service and it start in reboot automatically.
2.ss can write log into /var/log/ss.log without permission problem.