Day1: "Linux should be learned like this"

Knowledge points of this lesson:

1. When installing, you must choose to install the system later, otherwise it will perform a minimal installation without a graphical interface (do not choose server with GUI) 2. Choose
your own appropriate number of cores 8c16t (windows use task manager to view)
3 .No matter how much memory you have in your computer, choose 2G memory is enough (you are free!)
If it is less than 4G, choose 1G
, otherwise choose 2G (no matter how big the memory of the physical machine is, too much memory is wasted, it can meet all the needs of this book)
4. Remove the sound card or you will hear some beeps interrupting your thinking. Remove the USB controller and remove the printer and all other unnecessary things. The hard disk only needs 20G
5. Select the first option to install and press the Enter key It must be ringing when the phone is running (tell your computer not to make mistakes)
6. The time zone can be selected in China, and China does not distinguish between time zones
7. Be sure to choose server with gui (otherwise there is no graphical interface)
8. The user name is created In order to create a user named linuxprobe as in this book
9. Skip a manual that no one will read
10. Disabling Kdump can save 128MB of memory (used to collect error messages when your kernel has problems)
11. The next interface is a Red Hat advertisement and you can choose no (unlike the activation of the windows system, you can choose no at all)
12. When logging in to the system, choose not list and use the root account to log in (to avoid future due to permissions) Error caused by the problem)
13. Skip resetting the root password first
14. Compile the source code (1). The installation is difficult and complex (2). You need to solve the dependencies yourself
15. The source code and installation rules form the rpm package
16.yum is to solve the dependency problem of rpm package
17.rhel 5,6 innit (1)service (2)chkconfig rhel 7 systemd (1)systemctl (2)systemctl 18.systemctl
: (1)stop to close the service (2) start to enable the service (3) restart to restart the service (4) enable to join the startup item (5) disable
to cancel the startup item (6) status to check the status of the service
20. shell=lecturer bash=Lao Liu
21. Command parameter object (command: hit parameter: ruthless object: Xiaoming)
22. Parameter is a supplementary description to the command to make our tools more adaptable to the environment (on the sushi knife There are holes)
23. The short format is generally a letter and the long format is generally a word
24. The parameters can be combined (ls -a -l : ls -al)
25. Two long formats cannot be combined, one long format and one short format All short forms that cannot be merged can be merged and only need one "-"
26. Use the " $" symbol to call the environment variable ($ PATH)
27. The author of each command is different and there will be slight differences. For example, the date command is connected with a plus sign. 28. There
must be spaces between the parameters of the linux command and strict Case-sensitive
29. Output year, month, day, hour, minute and second: date "+%Y-%m-%d %H:%M:%S"
30. Restart command: (1)poweroff (2)shutdown now (3 )init 0
31.ps View the current system running information similar to the human task manager in windows
32. (1) R: running (running) (2) S: sleeping (dormant) (3) D: die (the process cannot be interrupted, not responding) (4) Z: zombie (zombie process, dead, does not provide services for users, but has been consuming system resources) 33.ps aux Displays detailed information of all processes including the
system
34. The top command is a real-time dynamic and more detailed
top - 09:00:30 up 1:29, 3 users, load average: 0.23, 0.28, 0.29 The
current time, the number of terminals and the load of the boot time (1 5 15)
35 .The graphical interface is also considered a terminal, so it will be one more than the number of terminal emulators.
36.buffers refers to the exchange value cache with the hard disk
37.pid is the identifier of the process, which is random.
38.load average is a calculated value, not a percentage. If it is less than 1, the CPU can solve it as soon as it comes out. The
smaller the value, the better (based on experience, 5 can't sleep)
39. Lao Liu finally took out the stalk of the house to solve the problem of the value of average load
40. Both killall and systemctl stop foo commands can solve all processes at once
41. kill + service number killall + service name
42 .kill -9 + the name of the service is to force shutdown