Qbittorrent is my preferred client on the server. It has a webui built in and can be started as a daemon.

I used this guide: https://github.com/qbittorrent/qBittorrent/wiki/Setting-up-qBittorrent-on-Ubuntu-server-as-daemon-with-Web-interface to set it up.

Install

qBittorrent-nox is already included in the official Ubuntu repositories. So you have to install the package by issuing the following command:

sudo apt-get install qbittorrent-nox

Initscript

Next up you’ll want to setup an initscript to maintain the qbittorrent-nox daemon and logging. First we create the file:

sudo touch /etc/init.d/qbittorrent

Now open up this file with a text editor to copy the contents in:

sudo nano /etc/init.d/qbittorrent

Once there, paste the following initscript into the file:

#! /bin/sh
### BEGIN INIT INFO
# Provides:          qbittorrent-nox
# Required-Start:    $remote_fs $syslog
# Required-Stop:     $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Starts QBittorrent
# Description:       Start qbittorrent-nox on start. Change USER= before running
### END INIT INFO

# Author: Jesper Smith
# Added log support and cleanup by DementedZA

#Edit the user that qbittorrent-nox will run as.
USER="qbituser"

# No need to edit these. Logging is sent to /var/log/qbittorrent-nox.log by default.
PATH="/sbin:/usr/sbin:/bin:/usr/bin"
SCRIPTNAME="/etc/init.d/qbittorrent"
NAME="qbittorrent-nox"
DESC="QBittorrent"
PIDFILE="/var/run/$NAME.pid"
QBTLOG="/var/log/$NAME.log"

DAEMON="/usr/bin/qbittorrent-nox"
DAEMON_ARGS=""
DAEMONSTRING="$DAEMON >> $QBTLOG 2>&1"

export DBUS_SESSION_BUS_ADDRESS=""

# Exit if the package is not installed
[ -x "$DAEMONPATH$DAEMON" ] || exit 0

# Read configuration variable file if it is present
#[ -r /etc/default/$NAME ] && . /etc/default/$NAME

# Load the VERBOSE setting and other rcS variables
. /lib/init/vars.sh

# Define LSB log_* functions.
# Depend on lsb-base (>= 3.0-6) to ensure that this file is present.
. /lib/lsb/init-functions

#
# Function that starts the daemon/service
#
do_start()
{

    #Check for log file. If it doesn't exist, create it.
    if [ -f $QBTLOG ];
    then
            echo "Logging to $QBTLOG."
    else
            echo "Log file $QBTLOG doesn't exist. Creating it..."
            touch $QBTLOG
            chown $USER:$USER $QBTLOG
            if [ -f $QBTLOG ];
                    then
                            echo "Logfile created. Logging to $QBTLOG"
                    else
                            echo "Couldn't create logfile $QBTLOG. Please investigate."
            fi
    fi

        # Return
        #   0 if daemon has been started
        #   1 if daemon was already running
        #   2 if daemon could not be started

    start-stop-daemon --start --chuid $USER --test --quiet --make-pidfile --pidfile $PIDFILE -background --exec /bin/bash -- -c "$DAEMONSTRING" || return 1

    start-stop-daemon --start --chuid $USER --make-pidfile --pidfile $PIDFILE --background --exec bin/bash -- -c "$DAEMONSTRING" || return 2
    sleep 1
}

#
# Function that stops the daemon/service
#
do_stop()
{
    start-stop-daemon --stop --exec "$DAEMONPATH$DAEMON"
    sleep 2
    return "$?"
}


case "$1" in
  start)
    [ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$NAME"
    do_start
    case "$?" in
        0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
        2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
    esac
    ;;
  stop)
    [ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME"
    do_stop
    case "$?" in
        0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
        2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
    esac
    ;;
  status)
       status_of_proc "$DAEMON" "$NAME" && exit 0 || exit $?
       ;;
  restart|force-reload)
    log_daemon_msg "Restarting $DESC" "$NAME"
    do_stop
    case "$?" in
      0|1)
        do_start
        case "$?" in
            0) log_end_msg 0 ;;
            1) log_end_msg 1 ;; # Old process is still running
            *) log_end_msg 1 ;; # Failed to start
        esac
        ;;
      *)
        # Failed to stop
        log_end_msg 1
        ;;
    esac
    ;;
  *)
    #echo "Usage: $SCRIPTNAME {start|stop|restart|reload|force-reload}" >&2
    echo "Usage: $SCRIPTNAME {start|stop|status|restart|force-reload}" >&2
    exit 3
    ;;
esac

THe new script must be marked as executable:

sudo chmod +x /etc/init.d/qbittorrent

User Configuration

You should create the unprivileged user qbituser by issuing this command:

sudo useradd qbituser
sudo mkdir /home/qbituser
sudo chown qbituser:qbituser /home/qbituser

Initialization with first start

Now you’ll want to run qbittorrent to get it to generate the config file and show its disclaimer, which you’ll need to read and accept in order to continue:

sudo su qbituser -c qbittorrent-nox

You’ll see the following:

*** Legal Notice ***
qBittorrent is a file sharing program. When you run a torrent, its data will be made available to others by means of upload. Any content you share is your sole responsibility.

No further notices will be issued.

Press 'y' key to accept and continue...

Press ‘y’ key and press enter. You should see the following:

******** Information ********
To control qBittorrent, access the Web UI at http://localhost:8080
The Web UI administrator user name is: admin
The Web UI administrator password is still the default one: adminadmin
This is a security risk, please consider changing your password from program preferences.
17/04/2014 16:52:29 - The Web UI is listening on port 8080
17/04/2014 16:52:30 - qBittorrent is successfully listening on interface 0.0.0.0 port: TCP/6881
17/04/2014 16:52:30 - qBittorrent is successfully listening on interface :: port: TCP/6881
17/04/2014 16:52:35 - External IP: XXX.XXX.XXX.XXX

Now that first run is accomplished, you can log in to your server’s IP address on port 8080. Say my server’s IP is 192.168.0.1, even though it says 0.0.0.0 its bound to your server ip, you can log in by going to http://192.168.0.1:8080 Username is ‘admin’ Password is ‘adminadmin’.

Once you have logged in and see that its working, you can proceed. Go back to the terminal and terminate the process by pressing ‘CTRL+C’. You can now start qbittorrent with:

Starting the Daemon

sudo service qbittorrent start

Configuration

Now you can log in to the web-server again and proceed to edit your config. If you need to get access to the config file:

sudo nano /home/qbituser/.config/qBittorrent/qBittorrent.conf

You can also monitor the running log with:

Logging

sudo tail -f /var/log/qbittorrent-nox.log

Running at Startup

If you would like qbittorrent to run at startup, update the initscripts with:

sudo update-rc.d qbittorrent defaults