Docker

docker pull jellyfin/jellyfin:latest
mkdir -p /srv/jellyfin/{config,cache}
docker run -d -v /srv/jellyfin/config:/config -v /srv/jellyfin/cache:/cache -v /media:/media --net=host jellyfin/jellyfin:latest

Ubuntu

sudo apt install curl gnupg
curl -fsSL https://repo.jellyfin.org/ubuntu/jellyfin_team.gpg.key | sudo gpg --dearmor -o /etc/apt/trusted.gpg.d/jellyfin.gpg
echo "deb [arch=$( dpkg --print-architecture )] https://repo.jellyfin.org/$( awk -F'=' '/^ID=/{ print $NF }' /etc/os-release ) $( awk -F'=' '/^VERSION_CODENAME=/{ print $NF }' /etc/os-release ) main" | sudo tee /etc/apt/sources.list.d/jellyfin.list
sudo apt update
sudo apt install jellyfin