1. List Linux distributions as required, and describe the connections and differences between different distributions.
- Slackware:
SUSE Linux Enterprise Server (SUSE Enterprise Edition), OpenSuse (SUSE Desktop Edition) - Debian：
ubuntu，deepin，mint - Redhat:
RHEL: RedHat Enterprise Linux, a new version is released every 18 months (open source, but some software packages need to be paid for use, and high support service fees, generally used by government, enterprises and institutions, these units are not bad for money)
CentOS: Community Enterprise Operating System compatible with RHEL format (removal of all copyright information of RHEL, free of charge for users to use, most companies use this open source operating system to deploy on the server, generally used by Internet companies)
Win the bid Kylin: Win the bid software (domestic Linux The operating system is based on the revision of the Redhat series)
Fedora: a new version is released every 6 months (Redhat desktop version, software update speed is fast, generally suitable for ordinary users to try and use) - Alpine:
A security-oriented lightweight Linux distribution. It is different from the usual Linux distributions. Alpine uses musl libc and busybox to reduce system size and runtime resource consumption, but it is more functionally complete than busybox, only about 5M in size (used to test dockers mirroring later) . - ArchLinux:
Lightweight and concise, follow the KISS principle (keep it simple and stupid), Manjaro - Gentoo:
extreme performance, does not provide traditional installation procedures, download the source code to compile and install the software on this machine - LFS:
Linux From scratch Self-made Linux, just a document, customize your own Linux system according to the document - Android:
kernel+busybox (tool set)+java virtual machine (usually used by Android phones)
2. Install the Centos7.6 operating system, create a user name with your own name, and log in normally, and take a screenshot of the main steps.
1) Install CentOS7 
2) It is recommended to choose English language 
3) Modify time (change to CST time) 
4) Choose American keyboard 
5) Choose minimal installation 
6) Disk partition 
7) Configure network 
8) Start to install operating system, and configure user name and Password 
9) Use ordinary account xyj to enter the operating system
3. Configure environment variables so that you can see the time of command execution when you execute history.
[root@centos8mini ~]# export HISTTIMEFORMAT="date +%F_%T "
4. Summarize Linux philosophy.
1) Everything is a file;
2) A single user program
3) Multiple commands are combined to form a complex task
4) Character interface
5) All configurations are saved in the configuration file
5. Summarize the format of commonly used Linux commands and illustrate with examples. For example, commands such as echo, screen, date, ifconfig, and export.
Command format: command [option] [argument]
Option (optional): short option, long option, BSD style option
parameter (optional): the object of the command. For example: file name, directory, etc.
echo [-neE] [arg ...]
date [OPTION]... [+FORMAT]
ls [OPTION]... [FILE]...
export [-fn] [name[ =value] ...]
history -anrw [filename]