常用命令

备份文件

$ cp /etc/nova/nova.cof{,.bak}

无密码sudo

$ sudo chmod 740 /etc/sudoers

$ sudo vim /etc/sudoers

#  在最下边添加如下内容
# stack是需要无密码执行sudo的用户
stack    ALL=(ALL) NOPASSWD: ALL

recovery mode进入read-write模式

$ mount -o rw,remount /

ubuntu 16.04 Desktop Setting

# 底部
gsettings set com.canonical.Unity.Launcher launcher-position Bottom

# 左边（Default）
gsettings set com.canonical.Unity.Launcher launcher-position Left

# 启动器最小化_恢复
gsettings set org.compiz.unityshell:/org/compiz/profiles/unity/plugins/unityshell/ launcher-minimize-window true

# Ubuntu工作区(4列1行)
dconf write /org/compiz/profiles/unity/plugins/core/hsize 4
dconf write /org/compiz/profiles/unity/plugins/core/vsize 1

Mysql

# 查看现有连接
SHOW [FULL] PROCESSLIST;

# 查看DB size
SELECT table_schema AS "Database name", SUM(data_length + index_length) / 1024 / 1024 AS "Size (MB)" FROM information_schema.TABLES where table_schema = "memory" GROUP BY table_schema;

SELECT 
     table_schema as `Database`, 
     table_name AS `Table`, 
     round(((data_length + index_length) / 1024 / 1024), 2) `Size in MB` 
FROM information_schema.TABLES WHERE table_schema = "<your db_name>"
ORDER BY (data_length + index_length) DESC;