Original title: "nohup and & background running, process viewing and termination"
Original link: https://www.cnblogs.com/baby123/p/6477429.html
1.nohup
Purpose: Run commands without hanging up.
Syntax: nohup Command [Arg…] [&]
Regardless of whether the output of the nohup command is redirected to the terminal, the output will be appended to the nohup.out file in the current directory.
If the nohup.out file in the current directory is not writable, the output is redirected to the $HOME/nohup.out file.
If no file can be created or opened for appending, the command specified by the Command parameter cannot be invoked.
Exit status: This command returns the following exit values:
126 The command specified by the Command parameter can be searched but cannot be called.
127 An error occurred in the nohup command or the command specified by the Command parameter could not be found.
Otherwise, the exit status of the nohup command is the exit status of the command specified by the Command parameter.
2.&
Purpose: run in the background
Generally use two together
nohup command &
eg:
nohup /usr/local/node/bin/node /www/im/chat.js >> /usr/local/node/output.log 2>&1 &
Process ID 7585
View running background processes
（1）jobs -l
The jobs command only takes effect on the current terminal. After closing the terminal, the jobs running in the background can no longer be seen in another terminal. At this time, use ps (process view command)
（2） ps -ef
ps -aux|grep chat.js
a:显示所有程序
u:以用户为主的格式来显示
x:显示所有程序，不以终端机来区分
Note:
Use ps -def | grep to find the process is very convenient, the last line will always grep itself
Use the grep -v parameter to exclude the grep command
ps -aux|grep chat.js| grep -v grep
Use awk to extract the process ID
ps -aux|grep chat.js| grep -v grep | awk ``'{print $2}'
3. If a process can't get up, it may be that a certain port is occupied
View the process using a port
lsof -i:8090
netstat -ap|grep 8090
After viewing the process id, use the netstat command to view the port it occupies
netstat -nap|grep 7779
Use kill to kill and enter the city before starting
4. Terminate processes running in the background
kill -9 进程号
