Set sound output default on ubuntu

# lay thong tin name va port bang lenh

pacmd list-sinks

#output

1 sink(s) available.
  * index: 0
name: <alsa_output.pci-0000_00_1f.3.analog-stereo>
driver: <module-alsa-card.c>
flags: HARDWARE HW_MUTE_CTRL HW_VOLUME_CTRL DECIBEL_VOLUME LATENCY DYNAMIC_LATENCY
state: SUSPENDED
suspend cause: IDLE
priority: 9959
volume: front-left: 1847 /   3% / -93,00 dB,   front-right: 1847 /   3% / -93,00 dB
        balance 0,00
base volume: 65536 / 100% / 0,00 dB
volume steps: 65537
muted: no
current latency: 0,00 ms
max request: 0 KiB
max rewind: 0 KiB
monitor source: 0
sample spec: s16le 2ch 44100Hz
channel map: front-left,front-right
             Stereo
used by: 0
linked by: 0
configured latency: 0,00 ms; range is 0,50 .. 371,52 ms
card: 0 <alsa_card.pci-0000_00_1f.3>
module: 6
properties:
alsa.resolution_bits = "16"
device.api = "alsa"
device.class = "sound"
alsa.class = "generic"
alsa.subclass = "generic-mix"
alsa.name = "ALC3234 Analog"
alsa.id = "ALC3234 Analog"
alsa.subdevice = "0"
alsa.subdevice_name = "subdevice #0"
alsa.device = "0"
alsa.card = "0"
alsa.card_name = "HDA Intel PCH"
alsa.long_card_name = "HDA Intel PCH at 0xf7120000 irq 127"
alsa.driver_name = "snd_hda_intel"
device.bus_path = "pci-0000:00:1f.3"
sysfs.path = "/devices/pci0000:00/0000:00:1f.3/sound/card0"
device.bus = "pci"
device.vendor.id = "8086"
device.vendor.name = "Intel Corporation"
device.product.id = "a170"
device.product.name = "Sunrise Point-H HD Audio"
device.form_factor = "internal"
device.string = "front:0"
device.buffering.buffer_size = "65536"
device.buffering.fragment_size = "32768"
device.access_mode = "mmap+timer"
device.profile.name = "analog-stereo"
device.profile.description = "Analog Stereo"
device.description = "Built-in Audio Analog Stereo"
alsa.mixer_name = "Realtek ALC3234"
alsa.components = "HDA:10ec0255,102806bb,00100002 HDA:80862809,80860101,00100000"
module-udev-detect.discovered = "1"
device.icon_name = "audio-card-pci"
ports:
analog-output-lineout: Line Out (priority 9900, latency offset 0 usec, available: no)
properties:

analog-output-speaker: Speakers (priority 10000, latency offset 0 usec, available: unknown)
properties:
device.icon_name = "audio-speakers"
analog-output-headphones: Headphones (priority 9000, latency offset 0 usec, available: yes)
properties:
device.icon_name = "audio-headphones"
active port: <analog-output-speaker>

# set output
pacmd set-sink-port <name> <port>
pacmd set-sink-port alsa_output.pci-0000_00_1f.3.analog-stereo analog-output-headphones