Routine questions
1. Briefly describe the composition of the
computer in your own language. The computer is composed of arithmetic unit, controller, memory, output device, and input device.
2. Briefly explain the relationship between hardware, operating system, application software and users. The
logical sequence from top to bottom: user -> application software -> operating system -> hardware
users use software to perform a certain task, call the operating system through the interface , The operating system is connected to the hardware, and the hardware will calculate and output the results on the display
3. Briefly describe the philosophy of Linux,
everything is a
small file , a single-purpose program
linker to complete complex tasks to
avoid confusing interface
configuration data stored in text files
4, Linux command system which is divided into several types, elaborate execution order
divided into three kinds
order of execution: Aliases - internal command - external command
5. Use your own language to try to explain what redirection is, and give examples of redirecting
the executed commands to the specified file
standard output through standard input, standard output, and standard error : format COMMAND> file will be executed through >, >> The command is redirected to the
standard input in the file : format COMMAND <file through <The file on the right is executed according to the command on the left.
Standard error: the error or prompt information is redirected to the specified file
echo'hello'> a.txt echo'hello
'> a.txt
wc -l <a.txt
cat b.conf 2>> z.conf
Scenario
1. The leader Li checked a file aa.txt by cat on the server, prompting No such file or directory, and let Xiao Wang come to help see what the situation was. After a meal, Xiao Wang found that aa.txt is a link file. The backup server found the original file. After a while, Xiao Wang solved the problem of Lao Li viewing aa.txt. Please explain how Xiao Wang solved it.
The reason is that the source file of the soft link is deleted, and the source file found on the backup server is restored to the path where it was before the deletion.
2. Use the mail command to send a weekend condolence letter to your qq mailbox, and the screenshot shows the result