1.搜索Linux安装的库：sudo apt-cache search XXX 2.查看端口号：netstat -apn | grep 8085 3.查看运行的程序：ps aux|grep redis 4.停止nginx： ./nginx -s stop 5.重启nginx:./nginx -s reload 6.启动/停止Apache ：service apache2 start/stop 7.重启数据库：service mysql restart 8.清理dns 缓存:ipconfig /flushdns 9.Linux里设置环境变量的方法：export PATH=$PATH:/root/web 10.显示当前PATH环境变量:echo $PATH 11.创建数据库：create database xxx 12.数据库表索引的创建： a.CREATE INDEX indexName ON table_name (column_name); （可重复索引） b.CREATE UNIQUE INDEX index_name ON table_name (column_name) （不可重复索引） 或 a.ALTER TABLE tbl_name ADD INDEX index_name (column_list); b.CREATE UNIQUE INDEX index_name ON table_name (column_name) 13.删索引：DROP INDEX indexName ON mytable; 14。给字段设置默认值：ALTER TABLE test ALTER COLUMN case_status SET DEFAULT 'A'; 15.数据库创建表： CREATE TABLE pet_data( pet_data_id bigint(20) NOT NULL AUTO_INCREMENT, uuid VARCHAR(64) NOT NULL, name VARCHAR(64) NOT NULL UNIQUE, start_time bigint(20) NOT NULL, end_time bigint(20) NOT NULL, stay_time bigint(20) NOT NULL, visits int DEFAULT 1, time datetime DEFAULT CURRENT_TIMESTAMP, CONSTRAINT u_time UNIQUE (uuid,start_time), unique (name), PRIMARY KEY ( pet_data_id ) )ENGINE=InnoDB DEFAULT CHARSET=utf8; 16.修改字段名：ALTER TABLE video_square CHANGE name name text NOT NULL; 17.删除字段：alter table share drop maxuser; 18.添加字段：alter table friend add username int NOT NULL; 19.唯一字段：Alter table vcards add UNIQUE(account); 20.改变字段类型:alter table share modify sharetoken VARCHAR(64) NOT NULL; 21.转移其他表中的数据:insert into user_playback(id) select users_id from users; 注：把users表中的id全部加到user_playback中 22.复制一个表（格式）:CREATE TABLE users_message_tokens_map LIKE iviewsdb.users_tokens_map; 23.复制表中的数据:INSERT users_message_tokens_map SELECT * FROM iviewsdb.users_tokens_map; 24.Linux运行后台进程:nohup node app.js & 或 ./a.out & 25.连接redis命令:redis-cli -h 101.132.249.240 -p 6379 -a 123456 ，(shutdown)退出 26.连接redis集群：redis-cli -c -p 7000 27.备份数据库表数据 mysqldump -u root -p iviewsdb devices_events_temp> mySQL.sql; 28.加载备份的数据:source mySQL.sql 29.数据库查询:select count(*),COUNT(DISTINCT server) as addr from server_information WHERE time between 1505439478 and 1505439510 AND server="lancens"; 30.获取最近7天的数据:select date(time),count(*) from devices_events_temp where DATE_SUB(CURDATE(), INTERVAL 7 DAY) <= date(time) group by date(time); 31.获取最近的500条数据:select time from (select * from devices_events order by time desc) as time limit 500; 32.获取大于500条的数据:SELECT uuid,COUNT(*) AS nums FROM devices_events_temp GROUP BY uuid having nums>500; 33.多个列的UNIQUE约束：ALTER TABLE Persons ADD CONSTRAINT uc_PersonID UNIQUE (Id_P,LastName); 34.如需撤销UNIQUE约束：ALTER TABLE Persons DROP INDEX uc_PersonID 35.有则更新无则插入：replace into test(id,time) VALUES (1232,NOW());