These examples assume you have lego installed. You can get a pre-built binary from the releases page.
The web server examples require that the lego binary has permission to bind to ports 80 and 443.
If your environment does not allow you to bind to these ports, please read Running without root privileges and Port Usage.
Unless otherwise instructed with the --path command line flag, lego will look for a directory named .lego in the current working directory.
If you run cd /dir/a && lego ... run, lego will create a directory /dir/a/.lego where it will save account registration and certificate files into.
If you later try to renew a certificate with cd /dir/b && lego ... renew, lego will likely produce an error.