Typical UNIX questions

Source: Internet
Author: User
For more information about Linux technologies and applications, see the following section. [I = s] This post was last edited by lijiang

I. Fill in blank questions:

1. in UNIX systems, all data and programs are stored on (), and all programs run by the memory occupied by the UNIX host.

2. there are two traffic control methods: one is the hardware method. The CTS signal line of the () interface is allowed to be sent, the RTS signal line is the request to be sent, and the other is the software method, use flow control characters ().

3. A virtual terminal is a virtual terminal in UNIX that connects a PC to a UNIX host through (). The client runs the () Program, and the server runs the telnetd program.

4. Windows and Unix text files have different structures. UNIX lines only have () characters at the end, while Windows lines store () characters at the end.

5. the type of the symbolic connection file is l. The delete operation on the symbolic connection file deletes the () file, and all other operations will access the () file.

Ii. Single-choice questions:

1. The identifier of the character device file type is ().

A. p B. c C. s D. l

2. The following () file contains information about the user password.

A./etc/shadow B./etc/passwd C./etc/group D./etc/profile

3. When csh is started, the command in the () file in the user's home directory is automatically executed.

A. cshrc B .. logout C. autoexec D. config

4. In general, the directory where the device file is located is ()

A./home/root B./home C./D./dev

5. The three symbols of File Permission reading, writing, and execution are () in sequence ().

A. rwx B. xrw C. rdx D. srw

6. Use ls? The "al" command lists the following files. () files are symbolic connection files.

A.-rw-2 El-s users 56 Sep 09 :05 hello

B.-rwxrwxrwx 2 El-s users 56 Sep 09 11: 05 goodbey

C. drwxr -- r -- 1 El users 1024 Sep 10 zhang

D. lrwxr -- r -- 1 El users 2024 Sep 12 cheng

7. There is a file in the/home/stud1/wang directory. You can use () to execute commands in the background. This command outputs the content of the file to the file. copy file.

A. cat file>; file. copy B. cat>; file. copy

C. cat file. copy & D. cat file> file. copy &

8. If the current directory is/home, run the/home/stud1/test command ().

A. cd test B. cd/stud1/test C. cd stud1/test D. cd home

9. user1 and user2 belong to the users group. User1 has a file file1, which requires user2 to be able to modify the file1 file of user1. this file should have the () permission.

A. 744 B. 664 C.646 D.746

10. The system regards both the storage device and the I/O device as files and does not use files.

A. Directory B. Soft link C. I node table D. Floppy Disk

11. () The device is a character device.

A. hdc B. fd0 C. hda1 D. tty1

12. Which of the following does not belong to the content of the I node is ().

A. index information B. File Type C. Number of links D. File Name

13. To make shell use the current directory as one of the directories of the search command, set the environment variable ().


14. The permissions of members outside the group of a file are read-only. The owner has all permissions. If the permissions in the group are read and write, the permissions of the file are ().

A. 467 B. 674 C. 476 D. 764

15. Exit the shell in interactive mode and enter ().

A. ; B. ^ q C. exit D. quit

16. Set the current directory of the Super User root to/usr/local. After you type the cd command, the current directory of the user is ().

A./home B./root C./home/root D./usr/local

17. The identifier of the character device file type is ().

A. p B. c C. s D. l

18. () is in the file directory table.

A. I node number B. file length C. Data Pointer D. File Type

19. The access permission for file exer1 is rw-r --. Which of the following statements is correct if you want to increase the execution permission for all users and write permission for users in the same group ().

A. chmod a + x g + w exer1 B. chmod 765 exer1

C. chmod o + x exer1 D. chmod g + w exer1

20. There is a file in the/home/stud1/wang directory. You can use () to execute commands in the background. This command outputs the content of the file to the file. copy file.

A. cat file>; file. copy B. cat>; file. copy

C. cat file. copy & D. cat file> file. copy &

3. incorrect judgment: Correct "√" and incorrect "×"

1. Use the standard error output of the previous command as the standard input of the next command, which is called a pipeline.

2. The command for adding a user is adduser or useradd.

3. You can use the kill command to end the background process.

4. Symbolic connections are implemented on algorithm software, and hard connections are implemented on the data structure.

5. permissions for common files: read, write, and executable. Files that cannot be written cannot be deleted.

6. Modify the file content. The system does not need to modify the directory file, but needs to modify the content of the I node.

7. The directory has the execution permission, which means all files in the directory are executable.

8. The actual UID and valid UID of the same process are consistent.

9. If the permission of an object is-rws -- x-x, the object has the SUID permission.

10. cc-c try. c-o try> & err. list combines stdin into stdout and redirects it to the file err. list.

11. The file opened by the parent process before fork execution. The Parent and Child processes have the same file offset pointer.

12. Boot block (Block 0) is used to start the system. Only the boot block of the root file system is valid.

13. Each file corresponds to an I node, and the Directory item does not have an I node.

14. The disadvantage of the pipeline created by pipe is that it is only limited to communication between the same ancestor processes.

15. Named pipeline, which allows process access without common ancestor.

16. Run the mknod pipe0 p command to create an MPS queue. A file named pipe0 and of the p type is created.

17. You can also detach the root file system )".

18. The file system format of the root file system and the sub-file system must be the same.

19. If the directory has no write permission, all files in the directory cannot be written.

20. Run the umount command to remove an installed sub-file system.

Note: Short answer mainly involves command usage.

Example 1: What is the role of the shell command cat try1.c try2.c try. h> trysrc>? What is the role of the entire SHELL command?

A:> it is the output redirection symbol. The command is used to redirect the output of try1.c try2.c try. h to the trysrc file to complete file synthesis.

Example 2: count the number of successfully logged-on users in the system. What is the shell command?

Answer: who | wc-l

Reference answer:

I. Fill in blank questions:

1. (UNIX host hard disk) (CPU ).

2. (RS232) (Xon and Xoff ).

3. (network) (telnet ).

4. (line feed) (carriage return and line feed ).

5. (symbolic connections) (referenced by symbolic connections ).

Ii. single choice:

1-5 B A D

6-10 D C B C

11-15 D C

16-20 B A B D

Iii. incorrect judgment:

1-5C ×√ √ × 6-10 √ ××√ ×

11-15 √ ××√ 16-20 √ ×××√
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