[Unit] Description=ngrokd server [Service] Type=simpleType=forking User=ngrok Group=ngrok ExecStart=/bin/sh -c '/usr/local/ngrok/bin/ngrokd \ -tlsCrt /usr/local/ngrok/tls/srv-ngrok.cert \ -tlsKey /usr/local/ngrok/tls/srv-ngrok.key \ -domain="ioio.cool" \ -httpAddr=:8480 \ -httpsAddr=:8433 \ -tunnelAddr=:8422 >> /var/log/ngrokd.log 2>&1'2>&1 &' Restart=always KillMode=process [Install] WantedBy=multi-user.target You can see man systemd.exec, search keywords StandardOutput, and man systemd.service, serach keywords COMMAND LINES
This syntax is intended to be very similar to shell syntax, but only the meta-characters and expansions described in the following paragraphs are understood. Specifically, redirection using "<", "<<", ">", and ">>", pipes using "|", running programs in the background using "&", and other elements of shell syntax are not supported.