Clear mysql CLI command history

If the mysql configuration for history files was not changed then mysql by default stores the list of command used at the CLI (Command line interface) prompt in the file ~/.mysql_history

As a security precaution if the CLI is used to set passwords clear the history after using the CLI by deleting this file ~/.mysql_history

如果在mysql> 命令列下，有下過一些和password有關的命令，可直接修改家目錄下的 .mysql_history檔案，將敏感性資料刪除。