`MySql` Display lock status
```sql
SELECT thread_id, object_name, lock_type, lock_mode, lock_data, index_name, lock_status FROM performance_schema.data_locks;
```

`SSL` Check public and private key if match
```cmd
openssl x509 -noout -modulus -in certificate.crt | openssl md5
openssl rsa -noout -modulus -in private.key | openssl md5
openssl req -noout -modulus -in request.csr | openssl md5
```

`SSL` Test serve
```cmd
openssl s_server -cert certificate.crt -key private.key
```

`SSL` Request new certificate using existing private key
```cmd
openssl req -new -key existing_private.key -out new_req.csr
```

`SMTP` `SSL` Test STARTTLS
```cmd
openssl s_client -starttls smtp -crlf -connect smtp.gmail.com:587
```