The difference between CentOS and Ubuntu in Linux system

**In the new year, you guys should learn more. **
For a new beginning, I thought about something, and I would like to share one of them with you.

1、 Virtualization technology is mainstream

On the road to future testing, testing machines (not only testing, but also development and operation and maintenance) will be the mainstream in the future for virtualization** (personal opinions, different opinions are welcome to leave a message)**, what is virtualization? Let’s not talk about all kinds of high-level theoretical knowledge, just talk about Docker.

Docker is an open source application container engine, based on the Go language and open source following the Apache2.0 protocol.
Docker allows developers to package their applications and dependent packages into a lightweight, portable container, and then publish it to any popular Linux machine, which can also be virtualized.
Containers use the sandbox mechanism completely, and there will be no interfaces between them (apps similar to iPhone), and more importantly, the container performance overhead is extremely low.

Xiaohan’s work usually requires many test machines. Of course, these test machines are all virtual machines of various versions such as Windows7/10/Server2012. Building these virtual machines must take up a lot of resources; and the virtual machines are used to run Automated Case, after running for a long time, a large number of caches appear, the machine becomes slow and sluggish, and it is necessary to regenerate the virtual machine at regular labor costs, and it is necessary to build a virtual machine test environment for each maintenance. Very time-consuming and laborious.

But there is an artifact, the Docker mentioned above, you can put the automated Case on Docker to run, prepare the scripts in advance, automatically create some Dockers and run the test scripts every time you build, and close it after the run is over Wouldn't it save time and effort to delete Docker one by one? ** Deploying the environment in docker will be cleaner, better managed, easier to deploy, and reproducible, ** and it does not take up so many resources. For example **Selenium Grid+Python(Java)+Dockers. **

Because of the above thoughts, I learned about Dockers by myself, and Docker runs more on Linux systems, and the basic knowledge of Linux is not very strong, so Linux+Docker is synchronized to learn.

2. The difference between CentOS and Ubuntu

CentOS (Community ENTerprise Operating System) is one of the Linux distributions. It is compiled from the source code released by Red Hat Enterprise Linux in accordance with the open source regulations. Since it comes from the same source code, some servers that require high stability use CentOS instead of the commercial version of Red Hat Enterprise Linux.

Ubuntu is a Linux operating system based on desktop applications. Ubuntu is based on the Debian distribution and GNOME desktop environment. The difference from Debian is that it releases a new version every 6 months. The goal of Ubuntu is to provide general users with an up-to-date, yet fairly stable operating system built primarily of free software. Ubuntu has a huge community power, users can easily get help from the community.

Both are service-level operating systems commonly used by individuals and small teams in the current version. Many open source software and libraries can be easily installed in the software library provided online. Both are used.

Bash is a basic shell, so in many basic commands, the difference between ubuntu and centos is not very obvious, and ubuntu has to do better on the desktop interface. **Many people generally choose to learn linux from interest. It is ubuntu, after all, many people are still very used to operating under desktop graphics. **

There are still many differences in the usage habits and commands between Centos and Ubuntu. Here is a brief list:

The newly-created non-root users in centos do not have sudo permissions. If you need to use sudo permissions, you must add accounts and permissions in /etc/sudoers, so when you switch to the root account, you only need to enter: su, add the root account password. can.

In Ubuntu, the sudo+ command is generally used. If it is the first time to use, it will prompt to enter the password of the current user (instead of the root password, the root password needs to be set separately when Ubuntu is used for the first time)

In the online software installation, centos uses the yum command, and ubuntu uses the apt-get command. In addition, there is a method to search for a certain software from the software source in yum: yum search + software name
Centos comes from redhat, so centos supports rpm format installation, but ubuntu obviously does not support it.

**ubuntu system: **

Enter the command for ordinary users: sudo apt-get install vim-gtk** centos system: **** Enter the command for ordinary users: yum -y install vim***

After all, different releases are made by different companies. The location of many configuration files and the default file path are very different. This needs to be slowly realized during use.