Install ‘Oracle VM VirtualBox Extension Pack’ Attaching webcam to guest OS VBoxManage list webcams VboxManage controlvm "Ubuntu 16.04.3" webcam attach .2 reference Enabling Webcam in VirtualBox Guest OS on Windows Host

在线执行环境，缺点是需要注册 Oracle live SQL http://sqlfiddle.com/ 创建用户 alter session set "_ORACLE_SCRIPT"=true; CREATE USER TOM IDENTIFIED BY a12345678; GRANT CONNECT, RESOURCE, DBA TO TOM; GRANT select on tom.contacts TO TOM; REVOKE DBA FROM TOM; REVOKE select on tom.contacts FROM TOM; DROP USER TOM; -- 同时删除用户下的所有对象

查找lock select * from master.dbo.sysprocesses where DB_NAME(dbid)=’test’ and spid<>@@SPID; exec sp_lock exec sp_who2 SPID; select request_session_id, resource_type, resource_description, request_mode, request_status, request_owner_type from sys.dm_tran_locks; kill SPID; 查看表结构 SELECT COLUMN_NAME, DATA_TYPE, CHARACTER_MAXIMUM_LENGTH FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'yourTableName'; 日期 -- 当前时

例子： <script src="https://example.com/example-framework.js" integrity="sha384-oqVuAfXRKap7fdgcCY5uykM6+R9GqQ8K/uxy9rx7HNQlGYl1kPzQho1wx4JwY8wC" crossorigin="anonymous"></script> 生成 SRI 哈希的工具 shasum -b -a 384 example-framework.js | xxd -r -p | base64 reference Subresource Integrity - Web 安全 | MDN

针对Windows 10 version 1909 打开注册表编辑器 regedit 进入 计算机\HKEY_CURRENT_USER\SOFTWARE\Microsoft\Window

bash函数 将函数追加写入~/.bashrc文件即可持久化，否则只在当前shell session内有效，关闭即无效 不要忘记加完需要sourc

click File > Virtual Media Manager in the main VirtualBox window Select a virtual hard disk in the list and use the “Size” slider at the bottom of the window to change its size. Click “Apply” when you’re done boot ubuntu virtual machine, use GParted to Resize reference How To Enlarge a Virtual M

事先申请api key，免费额度足够用了(每月50w字符) curl测试 curl -s -X POST -H "Content-Type: application/json" \ \ --data "{ 'q': 'The Great Pyramid of Giza (also known as the Pyramid of Khufu or the Pyramid of Cheops) is the oldest and largest of the

下载下来的漫画合集是rar格式，放到perfectview里也不能读，只能解压出来把每一卷压缩成zip文件 以前还写了个sh好像，没想到一行就

安装java cd /home tar -xf OpenJDK8U-jdk_x64_linux_hotspot_8u212b04.tar.gz # temp export PATH=$PWD/jdk8u212-b04/bin:$PATH java -version # final vi /etc/profile > JAVA_HOME=/home/jdk8u212-b04 PATH=$PATH:$HOME/bin:$JAVA_HOME/bin export JAVA_HOME export PATH > # log out and log in wget -O- -q -T 1 -t 1 https://github.com/AdoptOpenJDK/openjdk8-binaries/releases/download/jdk8u212-b04/OpenJDK8U-jdk_x64_linux_hotspot_8u212b04.tar.gz.sha256.txt | sha256sum -c 安装tomcat sudo groupadd tomcat sudo useradd -s /bin/false -g tomcat -d /opt/tomcat tomcat cd /tmp curl -O