System V is system management software, not as popular as the newer systemd but it is still in use here and there. It basically keeps other processes running.

System V init scripts are usually placed in /etc/init.d.

vim /etc/init.d/service-name        # full script below
chmod +x /etc/init.d/service-name

# start the service:
service servine-name start
# or
/etc/init.d/servine-name start

# define to run at startup, Fedora and Amazon Linux
chkconfig --add servine-name
chkconfig --levels 0126 servine-name off
chkconfig --levels 345 servine-name on
chkconfig --list servine-name

# define to run at startup, Debian and Ubuntu
update-rc.d servine-name defaults

# remove `Defaults requiretty`, useless security measure that breaks the scripts
sudo nano /etc/sudoers

Example init.d script template:

#!/bin/sh
### BEGIN INIT INFO
# Provides:
# Required-Start:    $remote_fs $syslog
# Required-Stop:     $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Start daemon at boot time
# Description:       Enable service provided by daemon.
### END INIT INFO

working_dir="/home/ruksi"
cmd="do_stuff parameter1 parameter2"
as_user="ruksi"

service_name=`basename "$0"` # the file name
pid_file="/var/run/$service_name.pid"
stdout_log="/var/log/$service_name.log"
stderr_log="/var/log/$service_name.err"

get_pid() {
    cat "$pid_file"
}

is_running() {
    [ -f "$pid_file" ] && ps `get_pid` > /dev/null 2>&1
}

case "$1" in
    start)
    if is_running; then
        echo "Already started"
    else
        echo "Starting $service_name"
        cd "$working_dir"
        if [ -z "$as_user" ]; then
            sudo $cmd >> "$stdout_log" 2>> "$stderr_log" &
        else
            sudo -u "$as_user" $cmd >> "$stdout_log" 2>> "$stderr_log" &
        fi
        echo $! > "$pid_file"
        if ! is_running; then
            echo "Unable to start, see $stdout_log and $stderr_log"
            exit 1
        fi
    fi
    ;;
    stop)
    if is_running; then
        echo -n "Stopping $service_name.."
        kill `get_pid`
        for i in {1..10}
        do
            if ! is_running; then
                break
            fi
            echo -n "."
            sleep 1
        done
        echo
        if is_running; then
            echo "Not stopped; may still be shutting down or shutdown may have failed"
            exit 1
        else
            echo "Stopped"
            if [ -f "$pid_file" ]; then
                rm "$pid_file"
            fi
        fi
    else
        echo "Not running"
    fi
    ;;
    restart)
    $0 stop
    if is_running; then
        echo "Unable to stop, will not attempt to start"
        exit 1
    fi
    $0 start
    ;;
    status)
    if is_running; then
        echo "Running"
    else
        echo "Stopped"
        exit 1
    fi
    ;;
    *)
    echo "Usage: $0 {start|stop|restart|status}"
    exit 1
    ;;
esac

exit 0

Sources

• System V init script template