The course started as scheduled. Because there was no preview in advance, I felt that today's speed was a bit fast, but I still kept up with it. The main content of today’s course is summarized as follows:
1. Virtual machine system installation, RHEL7 installation
1) Memory size setting during installation:
<2G memory setting 1G
<4G memory setting 1~2G
4G memory can be set to 2G.
2) Network mode selection:
Bridge mode: the same network status as the physical host;
NAT mode: VM's virtual machine network service plays the role of a router;
Host-only mode: Cannot access the external network, only allow virtual The host of the computer communicates with the physical host.
2. RPM and Yum
RPM (Red Hat Package Manager) are a bit like the control panel of the Windows system, which will establish a unified database file, record software information in detail and automatically analyze dependencies.
Yum can analyze the required software packages and related dependencies according to user requirements, and then automatically download the software packages from the server and install them to the system.
3. The
systemctl restart service name restarts the service;
systemctl stop service name stops the service;
systemctl start service name starts the service;
systemctl status service name view service;
systemctl reload service name reloads the configuration file (does not terminate the service);
4. SHELL is a general term
for hardware management programs; among them, Bash is the choice of mainstream Linux systems; it
has the following four major advantages:
1) Use the up and down arrow keys to retrieve previously executed commands;
2) Commands or parameters only need to be entered before A few digits can be completed with the Tab key;
3) It has a powerful batch script;
4) It has a practical environment variable function;
5. The format of the Linux command:
command name, command parameters, and command objects are separated by space bar;
1) The object can be a file, a directory, or a user.
2) The parameter can be in long format or short format.
For example:
long format: ls --all
short format: ls -a
6. Commonly used system commands:
1) echo: command is used to output string or variable extracted value in the terminal.
2) data: used to display and set the time or date of the system
3) reboot: used to restart the system;
4) poweroff: used to shut down the system;
5) wget: used to download network files in the terminal;
6) ps: used To view the process status in the system;
7) top: used to dynamically monitor process activities and system load and other information.
8) pidof: Used to query the PID value of a specified service process.
9) kill command: used to terminate the service process of a specified PID
10) killall: used to terminate all processes corresponding to a service of a specified name,