libiconv解决办法：https://github.com/qbittorrent/qBittorrent/issues/11723
注意：
- 一定别先安装lnmp。由于lnmp编译安装了libiconv，会导致qbittorrent编译失败。
2.如果安装了，按照上面链接最后给出的方法解决，并且需要重新安装php。 - c++最低强制为c++17
##环境要求
apt install build-essential pkg-config automake libtool git zlib1g-dev libssl-dev libgeoip-dev
apt install libboost-dev libboost-system-dev libboost-chrono-dev libboost-random-dev
apt install qtbase5-dev qttools5-dev libqt5svg5-dev编译libtorrent
wget https://github.com/arvidn/libtorrent/releases/download/v1.2.12/libtorrent-rasterbar-1.2.12.tar.gz
tar xf libtorrent-rasterbar-1.2.12.tar.gz
cd libtorrent-rasterbar-1.2.12
./configure --disable-debug --enable-encryption --with-libgeoip=system CXXFLAGS=-std=c++17
make -j$(nproc)
make install
ldconfig编译qbittorrent
cd
git clone https://github.com/qbittorrent/qBittorrent
cd qBittorrent
git checkout v4_3_x
./configure --disable-gui CXXFLAGS="-std=c++17"
make -j$(nproc)
make install设置开机启动
nano /etc/systemd/system/qbittorrent.service粘贴以下内：
[Unit]
Description=qBittorrent Daemon Service
After=network.target
[Service]
LimitNOFILE=512000
User=root
ExecStart=/usr/local/bin/qbittorrent-nox
ExecStop=/usr/bin/killall -w qbittorrent-nox
[Install]
WantedBy=multi-user.target启用以上设置：
systemctl enable qbittorrent.service启动 qbittorrent 首次启动 请安 y 接受确认
qbittorrent-nox接着按 Ctrl+c 退出，启动后台运行
systemctl start qbittorrent.service至此 qbittorrent 安裝完成
访问 WebUI：http://你的IP:8080/ 默认用户名：admin 默认密码：adminadmin
关闭 qBittorrent 命令:
systemctl stop qbittorrent.service启动 qBittorrent 命令:
systemctl start qbittorrent.service重启 qBittorrent 命令:
systemctl restart qbittorrent.service