Tutorials about WordPress are already abundant, with varying quality. Below, I will share a story about upgrading WordPress using SSH, based on my own experience—putting new wine in old bottles.
1. You need to make sure that your FTP account has enabled SSH functionality (Users-Manage Users-edit-User Account Type: select shell account). After that, you can log in and manage via Putty.
2. Download a Putty client, enter your domain name and press Enter. Then, you can input your SSH account and password to access the root directory of your blog.