optional, but recommended
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys BA300B7755AFCFAE
add Typora's repository
添加
sudo add-apt-repository 'deb https://typora.io linux/'
刪除
sudo add-apt-repository -r 'deb https://typora.io linux/'
sudo apt-get update
install typora
sudo apt-get install typora