October 5, 2020 linux

1. Install vmware workstation 16 or 15.5
2. Create a virtual machine-choose advanced-do not choose the OS immediately, choose to install the operating
   system later. Choose linux 8 64 bit-fill in the name of the virtual machine-the minimum disk is 20G.
   Regarding memory: minimum 1G, maximum 2G, there is no business division too much Waste
   network: host mode only
   Other: remove USB/sound card/printer
3. Install linux8
   edit virtual machine hardware--cd select the corresponding OS
   select install RedHat Linux 8
   language select english
   software selection select server with GUI
   Kdump remove enable (default enabled will automatically occupy 160M of memory space for storing error messages when the kernel fails)
   creation Root password, you can create other accounts at the same time

4. RPM Redhat Package Manager Red Hat Package Manager: Manage software package dependencies
   Yum software warehouse (Yum4.0 name is DNF): Provide required software packages and dependencies according to user needs

5. Initialization process:
   System V init before redhat7, now systemd.
   The initialization process is started after the kernel is started. It is the first startup process of the system. It performs system initialization to provide users with a suitable working environment.
   systemdctl restart/reload
   systemdctl start/stop/status/enable (add startup items)
6. bash shell---human-computer interaction
   command parameter object, the parameters are divided into long and short formats (-a letters, --all words)
7. Command:
   echo
   date
   timedatectl set-time
   reboot
   poweroff/shutdown/halt/init0
   wget
   ps (R start state/S sleep state/D uninterruptible/Z zombie process/T stop state)
   pstree process dependency
   top real-time process status
   psidof
   kill/ killall (a process has multiple pdid)