Centos8.5无法用yum安装screen,iftop,nethogs等的解决办法

环境：Centos8.5；
说明：进程在执行的过程中如果由于终端窗口关闭的话，那么该进程也会随着停止，这样就回很麻烦
下面引入我们今天的对象-screen（可以保证由于终端窗口关闭以后进程依然在执行）
但是Centos8.5通过yum直接安装screen会报错

[root@centos8 ~]#screen
-bash: screen: command not found

[root@centos8 ~]#yum -y install screen
CentOS Linux 8 - AppStream                                  3.9 kB/s | 4.3 kB     00:01    
CentOS Linux 8 - BaseOS                                     6.9 kB/s | 3.9 kB     00:00    
CentOS Linux 8 - Extras                                     1.9 kB/s | 1.5 kB     00:00    
No match for argument: screen
Error: Unable to find a match: screen

[root@centos8 ~]#yum -y install screen
Last metadata expiration check: 0:02:06 ago on Wed 11 May 2022 11:30:57 PM CST.
No match for argument: screen
Error: Unable to find a match: screen

为什么会报错呢？------这是由于Centos8yum源里没有epel，但是呢screen、iftop、nethogs是在epel里面的，所以解决办法就是：
1.安装epel
2.通过screen

[root@centos8 ~]#yum -y install epel-release
Last metadata expiration check: 0:23:55 ago on Wed 11 May 2022 11:30:57 PM CST.
Dependencies resolved.
============================================================================================
 Package                  Architecture       Version               Repository          Size
============================================================================================
Installing:
 epel-release             noarch             8-11.el8              extras              24 k

Transaction Summary
============================================================================================
Install  1 Package

Total download size: 24 k
Installed size: 35 k
Downloading Packages:
epel-release-8-11.el8.noarch.rpm                             42 kB/s |  24 kB     00:00    
--------------------------------------------------------------------------------------------
Total                                                        42 kB/s |  24 kB     00:00     
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                                    1/1 
  Installing       : epel-release-8-11.el8.noarch                                       1/1 
  Running scriptlet: epel-release-8-11.el8.noarch                                       1/1 
  Verifying        : epel-release-8-11.el8.noarch                                       1/1 

Installed:
  epel-release-8-11.el8.noarch                                                              

Complete!

[root@centos8 ~]#yum -y install screen
Extra Packages for Enterprise Linux 8 - x86_64              1.7 MB/s |  11 MB     00:06    
Extra Packages for Enterprise Linux Modular 8 - x86_64      386 kB/s | 1.0 MB     00:02    
Last metadata expiration check: 0:00:02 ago on Wed 11 May 2022 11:56:11 PM CST.
Dependencies resolved.
============================================================================================
 Package             Architecture        Version                    Repository         Size
============================================================================================
Installing:
 screen              x86_64              4.6.2-12.el8               epel              581 k

Transaction Summary
============================================================================================
Install  1 Package

Total download size: 581 k
Installed size: 955 k
Downloading Packages:
screen-4.6.2-12.el8.x86_64.rpm                              715 kB/s | 581 kB     00:00    
--------------------------------------------------------------------------------------------
Total                                                       201 kB/s | 581 kB     00:02     
Extra Packages for Enterprise Linux 8 - x86_64              1.6 MB/s | 1.6 kB     00:00    
Importing GPG key 0x2F86D6A1:
 Userid     : "Fedora EPEL (8) "
 Fingerprint: 94E2 79EB 8D8F 25B2 1810 ADF1 21EA 45AB 2F86 D6A1
 From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-8
Key imported successfully
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                                    1/1 
  Running scriptlet: screen-4.6.2-12.el8.x86_64                                         1/1 
  Installing       : screen-4.6.2-12.el8.x86_64                                         1/1 
  Running scriptlet: screen-4.6.2-12.el8.x86_64                                         1/1 
  Verifying        : screen-4.6.2-12.el8.x86_64                                         1/1 

Installed:
  screen-4.6.2-12.el8.x86_64                                                                

Complete!

#执行screen（页面会清空，说明执行成功了）
[root@centos8 ~]#screen