Shulou(Shulou.com)06/03 Report--

1. Change the permissions of a file or directory

Q: create the file a.txt, change the user master of the file to read-write execution, the user group to read-write, and the rest to read-only

A:

Create: files can be created with vim.

Modify permissions: the default permission after creation is-rw-r--r--, adds the execution permission of the user head and the write permission of the user group according to the requirements of the problem. The command is as follows:

Chmod upright x a.txt

Chmod Grouw a.txt

A:touch a.txt

Chmod 764 a.txt

two。 Copy command

Q: copy the a.txt file to a b.txt file while preserving the properties of the source file

A:cp-p a.txt b.txt

3. Cut a file

Q: displays the 2nd to 8th characters of each line of the file

A:cut-c 2-8 a.txt

4. Generate difference information

Q: compare the differences between the two files and generate the difference information

A:diff filename1 filename2

5. Identify the file type

Q: show the file types under the / var/log folder

A:ls-l / var/log

A:file / var/log

6. Find a directory or file

Q: find the file name under / usr/bin is openssl file

A:find / usr/bin-name "openssl"

Q: find files that have been modified within 24 hours under the home directory

A:find / home-mtime-1

Q: find files that have been modified within 30 minutes under the home directory

A:find / home-mmin-30

7. Link a file or directory

Q: establish a symbolic link to the file a.txt la.txt

A:ln-s a.txt la.txt

8. Merge the columns of a file

Q: a.txt b.txt is merged column by column and output to standard output.

A:paste a.txt b.txt

9. Package and compress and extract files at the same time

Q: package a.txt and b.txt to c.tar.gz

A:tar zcvf c.tar.gz a.txt b.txt

10. Read data from standard input to standard output and save it as a file

Q: export the file a.txt to standard output and save it as d.txt

A:cat a.txtwitcp a.txt d.txt

A:cat a.txt | tee d.txt

11. Sorting of text content

Q: sort the output of the file a.txt in reverse order

A:tac a.txt

A: sort-r a.txt

twelve。 Show working directory A:pwd

13. Display or configure network devices

Q: displays the working status of the current network device

A: ifconfig

14. Show network status

Q: displays the network status in the listening state of the system

A:netstat-anp | grep LISTEN

15. Encrypted remote login

Q: log in to 172.17.0.20 remotely with quwenqing user

A:ssh quwenqing@172.17.0.20

16. Kill the process in progress

Q: find out the processes in the system that contain the php keyword and kill one of them

A:ps-auxww | grep php

Kill-9 xxx

17. Execute an order in another capacity

Q: display disk usage as root

A:sudo df-h

18. Set or display environment variables

Q: set the environment variable A=ttt to display the environment variable

A:export A = "ttt"

Echo $A

19. Awk displays the matching line containing ab in the file a.txt

A:awk'/ ab/ {print} 'a.txt

20. Awk displays the current record number of the file a.txt, the number of fields, and the first and last fields of each line.

A:awk'{print NR,NF,$1,$NF} 'a.txt

21. Use awk filtering to check the number of connections in netstat

A: netstat-an | awk'/ ^ tcp/ {A [$NF] + +} END {for (an in A) print a, A [a]}'

twenty-two。 Delete 3-5 lines from the a.txt with sed, replace all a with A, and output to the monitor

A:sed '3pm 5d incense a.txt an Accord A Universe

A: sed-e '3mai 5d'-e's Unip. A Unique Amax g 'a.txt

F.A.H ^ _ ^ Amber

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