How do I automatically start the token server on Linux?

The easiest way to achieve this is by creating or extending the file /etc/rc.local, which is executed when the system has booted. This file should look something like this:

#!/bin/bash
/opt/gurobi1103/linux64/bin/grb_ts
exit 0

In addition, you need to change the permissions of the rc.local file such that it can be executed by running

sudo chmod +x /etc/rc.local

You can also use cron to start the token server process after every reboot. As user root, you need to open the cron configuration using

crontab -e

Then, you can enter the command to start grb_ts after a restart:

@reboot /opt/gurobi1103/linux64/bin/grb_ts

To check whether the new cron command has been registered, you can run

crontab -l

systemd can be configured to run the token server as a "simple" service type.  To set this up, create a service file at /etc/systemd/system/grb_ts.service with the following contents:

[Unit]
Description=Gurobi Token Server
After=network.target

[Service]
Type=simple
ExecStart=/opt/gurobi1103/linux64/bin/grb_ts -n
Restart=on-failure

[Install]
WantedBy=multi-user.target

The important points to note here are that the service type is set to simple, and that grb_ts is run with the -n switch so that it does not fork when started.

To inform systemd of this new service file, start the service, and set it to start automatically when the system boots, run the following:

sudo systemctl daemon-reload
sudo systemctl start grb_ts
sudo systemctl enable grb_ts

The status of the service can then be checked using:

sudo systemctl status grb_ts

Please also note that in this case the token server is run as the root user, so the license file should be installed at the default location /opt/gurobi/gurobi.lic, not in the account of a particular user.