To answer this question, you must first understand two basic knowledges based on Linux systems:

The copyright of Linux systems and the business model of Redhat.

The relationship between CentOS and Redhat Enterprise.

Let’s talk about it one by one:

The Linux system itself is free and open source software. Simply put, everyone can get a copy of the system and can freely copy, install, and modify it. However, because RedHat has invested a lot of manpower and material resources in Linux-based development and issued RedHat Enterprise (RHEL for short), they use an authorized release method for RHEL. Only customers who have purchased corresponding services can use RHEL's technical support and system upgrades. Service, so RHEL is a paid system.

Secondly, since RHEL itself is also developed based on the Linux system, it also needs to comply with the free software agreement. When releasing the packaged system, it may also need to release its source code files. Hence the CentOS system.

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 code regulations. Because 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.

The relationship between the two:

When RHEL was released, there were two ways. One is a binary distribution method, and the other is a source code distribution method. Regardless of the distribution method, you can obtain it for free (for example, download it from the Internet) and redistribute it. But if you use their online upgrades (including patches) or consulting services, you have to pay. RHEL has always provided source code distribution. CentOS recompiles the source code released by RHEL to form a usable binary version. Since the source code of LINUX is GNU, it is legal to obtain the source code of RHEL and compile it into a new binary. It's just that REDHAT is a trademark, so the REDHAT trademark must be removed in the new release. REDHAT's attitude towards this kind of distribution is: "We are actually not opposed to this kind of distribution. The users who really pay us do not value the system itself, but the commercial services we provide." Therefore, CentOS can Get all the features of RHEL, even better software. However, CentOS does not provide commercial support to users, and of course does not bear any commercial responsibility. If you are moving your RHEL to CentOS because you don't want to pay for RHEL upgrades. Of course, you must have extensive experience using Linux, so RHEL's commercial technical support is not important to you. But if you are a pure business enterprise, it is still recommended that you purchase RHEL? software and purchase corresponding services. This saves you money on IT management costs and provides you with professional services. In a word, whether to choose CentOS or RHEL depends on whether your company has the corresponding technical strength.

So CentOS and RHEL are actually systems compiled from the same source code, so learning either one can be applied to other systems. In addition, the differences between each distribution are nothing more than minor adjustments to commands and differences in tools, so if you learn any version, you can apply it on other Linux.

Since Redhat has launched a series of training tutorials for RHEL, they are very detailed and can be easily downloaded online.

For versions: The versions of CentOS and RHEL are basically synchronized, and the current highest version is 6.4.

For other related information, you can have a comprehensive understanding of the Linux system as a whole.

References:

Centos: /link?url=SrSZlJO3m9JcjO7UhpVH4Xxl0VJI8sOrqVLREBQ9VMmjr-5f25qkFCp1vkDLoXea

Redhat: /view/897468.htm