Demonizing a command means to make it run as a background process.

so when we have a command that we want to daemonize there are many ways to do it, most common methods are:

1. using upstart
2. adding it to /etc/rc.local
3. creating a script in /etc/init.d and adding them to runlevel folders manually (i.e. incase you want to start, stop a command)

Most easiest seems to be using supervisor

Installing Supervisor and sample configuration file:

installing it in ubuntu or any Debian based system is as simple as

sudo apt-get install supervisor

now you can create your configurations in /etc/supervisor/conf.d/ folder with extension ".conf"

a simple configuration file at /etc/supervisor/conf.d/test-program.conf will look as

[program:]

command = 

stdout_logfile = 

stderr_logfile = 

logfile_maxbytes = 50MB      ; optional 

logfile_backups = 10         ; needed if you want to rotate log files

user = root                  ; user as which the script should be executed

environment=variable1='value',variable2='value'    ; environment variale to pass if any

Daemonizig the command:

supervisorctl reread
supervisorctl update

The first command re-reads the configuration files and detects any changes

The second command updates the supervisor process with the new or changed configurations.

Now you have daemonized the command as background process

Other useful commands:

Stopping a process:

sudo supervisorctl stop 

sudo supervisorctl stop all

starting a process

sudo supervisorctl stop

restarting a process

sudo supervisorctl restart 

sudo supervisorctl restart all