mkdir -p ~/.config/systemd/user
vi ~/.config/systemd/user/tmux.service
输入以下内容：

[Unit]
Description=tmux default session
After=network.target

[Service]
Type=oneshot
ExecStart=/bin/sh -c '/usr/bin/tmux has-session -t aaaaaaaaaaaaaaaaaaaaaaaa || /usr/bin/tmux new-session -d -s aaaaaaaaaaaaaaaaaaaaaaaa'
ExecStop=/usr/bin/tmux kill-session -t aaaaaaaaaaaaaaaaaaaaaaaa
RemainAfterExit=yes

[Install]
WantedBy=default.target

systemctl --user daemon-reload
systemctl --user enable tmux
systemctl --user start tmux
systemctl --user status tmux.service    # 查看服务状态

让“用户服务”随开机启动
loginctl enable-linger $USER
验证：
loginctl show-user $USER | grep Linger
看到 Linger=yes 就对了。