mysql”客户使用MYSQL_HISTFILE环境变量中命名的文件来保存命令行历史，历史文件的缺省值是“$HOME/.mysql_history”，这里$HOME是HOME环境变量的值。-mysql " customers MYSQL_HISTFILE environment variable named file to save the command-line history, historical documents, the default value is"　$ HOME/.mysql_history " , where $ HOME is the HOME environment variable' s value.