How to daemonize a process

TL; DR: detach the (daemon) process (via setsid)

1. In parent process: fork

2. In parent process: exit

3. In child process: setsid maybe...
   3.1. In child process: fork again => child process B
   3.2. In child process: exit
   3.3. In child process B: setsid

4. In child process (maybe B): set umask

5. In child process (maybe B): set I/O redirection

6. In child process (maybe B): close other fds

7. In child process (maybe B): change workdir to /

8. In child process (maybe B): fork/exec the process to run

In Bash

(Warning: Just worked in Linux)

# Usage
./daemonize.sh [command]

ps -ef | grep daemonize.sh
# PPID => 1 (init)