Linux theoretical knowledge points (for exams)

PS: For its 10 days or so the Linux training is coming to an end, ahead of schedule, in order to better pass after the exam, read more exam questions and knowledge points in advance. This is a post that you see in the Chinaunix forum, posted to share.

Original address: "Http://bbs.chinaunix.net/thread-3668921-1-1.html"

A Fill in the blanks questions:
1. In a Linux system, access the device as a file.
2. When booting from the Linux kernel, read the file system to be loaded from the file/etc/fstab.
3. Each file in the Linux file system is identified by an index node.
The Linux file system uses an index node to log file information, like a file allocation table for Windows, an index node is a data structure that contains file name, location, size, build or modify time, access rights, affiliation, and other document control information for a file, A file system maintains an array of index nodes, each of which corresponds to the only element in the index node array, and the system assigns a number to each index junction, which is the index number of the node in the arrays, called the index node number.
The Linux file system keeps the file index node number and filename in the directory at the same time, so the directory is simply a table that combines the name of the file with its index node number. Each pair of file names and index nodes in the directory is called a connection.
4. All disk blocks consist of four parts, namely the boot block, the private block, the I node table block, and the data storage block.
Each file in the Linux system is given a unique value, which is called the index node. The index nodes are stored in a table called an index node, the Inode table>, which is allocated when the disk is formatted. Each actual disk or partition has its own table of index nodes. An index node contains all the information about the file, including the address and file type of the data on disk. File types include information such as normal files, directories, and special files.
The Linux hard disk is organized as: Boot Zone, super block (superblock), index node (inode), data Block (DataBlock), directory block (Diredtory block). The Super block contains the overall information about the file system on the hard disk or partition, such as the size of the file system, etc. the data structure behind the Super block is an index node that contains almost all the information about a specific file, such as access to a file, owner, size, settling time, and corresponding directory block and data block. The data block is the location where the contents of the file are actually stored. However, the name of the file is not included in the index node, and the filename is placed in the directory block. The directory block contains the name of the file and the index node number of the file.

5. Links are divided into: hard links and symbolic links.
6. The Super block contains important file system information such as the I node table and the free block table.
7. The permission for a file is: drw-r--r--, which is a numeric representation of the permission, the octal number is: 644, the file property is a directory.
8. The foreground START process uses CTRL + C to terminate.
9. After the static route is set, if the network topology changes, the system administrator should modify the routing settings.
10. The important tasks of network management are: control and monitoring.
11. When installing a Linux system on a hard disk partition, there must be two types of partitions: File system partition and swap partition.
13. The script file must be given permission to execute before the shell program is written.
14. One of the tasks of system management is the ability to secure, backup, restore, and update programs and data in a distributed environment.
15. The system swap partition is an area of system virtual memory.
16. The kernel is divided into four subsystems such as process management system, memory management system, I/O management system and file management system.
17. Kernel configuration is an important operation that the system administrator will take when changing the system configuration hardware.
18. In the installation of a Linux system, the network is configured with the Netconfig program, which prompts the user to enter the necessary information such as hostname, domain name, domain name server, IP address, gateway address, and subnet mask step-by-step.
19. The user ID and user name are uniquely identified for each user.
20. RIP protocol is the most common kind of internal protocol, which is generally called Dynamic routing protocol.
21. All content in a Linux system is represented as a file, and various methods of organizing the file are called file systems.
DHCP can implement dynamic IP address assignment.
23. The Management objects of the System network administrator are the processes of the server, the user and the server, and the various resources of the system.
24. Network management is usually composed of three parts: monitoring, transmission and management, in which the management part is the center of the whole network management.
25. You must compile the kernel when you want to remove device drivers that are not used by the system, and you must upgrade the kernel when the kernel does not support device drivers on the system.
The ping command can test whether a local system in the network can reach a remote host, so it is often used to test the connectivity of the network.
The VI editor has two modes of operation: Command mode and input mode.
28. You can use the Ls–al command to observe the permissions of the file, each file's permissions are represented by 10 bits, and divided into four segments, where the first paragraph accounted for 1 bits, representing the file type, the second paragraph accounted for 3 bits, indicating the file owner's permission to the file.
29. The difference between the process and the program is that its dynamic, dynamic generation and termination, from the generation to the termination process can have the basic state: the Operation state, the ready state and the waiting state (blocking state).
In fact, DNS is a database of host information distributed over the Internet, which is implemented to convert between IP addresses and host names.
Apache is an application that implements the WWW server function, which is commonly referred to as the "Browse Web Server", which is the Apache application that provides the user with a browse Web service on the server side.
32. There are two types of backups that can be made on Linux systems: System backup and user backup. The former refers to the backup of the operating system, which refers to the backup of the application and user files.
The CD-ROM standard file system type is iso9660.
34. When the lilo.conf is configured to take effect, the command and parameters that should be run are lilo.
35. When using the LS command, use the parameter-B to display non-printable characters in octal form.
The type of file system that Linux uses to support long file names for Windows 9.x/2000 is VFAT.
37. Set the command that restricts the user's use of disk space is quota.
38 in a Linux system, the directory used to store the configuration files and subdirectories required by the system is/etc.
39. Hard connections can only establish links to files. Symbolic links can be created across different file systems.
40. The property bit of the socket file is S.
41. The command to end the background process is kill.
42. The process runs in two ways, running independently and using the parent process.
Links are divided into hard links and symbolic links.
44. Under Superuser display all the processes running on the Linux system, the commands and parameters that should be used are ps-aux.
45. The attribute bit of the pipe file is p.
46. Use the standard output of the previous command as the standard input for the latter command, called a pipeline.
47. The command and parameter specifying the execution authority for the script is chmod a+x filename.
48. The command to Telnet is telnet.
49. To send 10 packet packets to test the connectivity to the host abc.tuu.edu.cn, the command and parameters that should be used are: Ping abc.tuu.edu.cn–c 10.
The DNS server's process is named named, and when it starts, it automatically loads the DNS partition database files defined in the named.conf file in the/etc directory.
The Apache server process configuration file is httpd.conf.


52. In a Linux system, the command to generate a suffix. gz file after compressing a file is gzip.
53. When editing a file with VI, save the contents of the file in the Test.txt file, type: w test.txt in command mode.
54 commands and parameters that can display the full year calendar on standard output are cal-y.
55. In shell programming, the rule using square brackets to denote test conditions is that there must be spaces on either side of the square brackets.
56. Check if the installed file system/dev/had5 is normal, if the check is wrong, the automatic repair, its command and parameters are FSCK–A/DEV/HAD5.
57. One tool for sharing the user directory in Unix/linux in a windows9.x environment is the samba server.
58. The system administrator's responsibility is to carry out system resource management, systematic performance management, equipment management, security management and system performance monitoring.
59 in a Linux system, test whether the DNS server can correctly resolve the client commands for the domain name, using the command nslookup.
60. Under the Linux system, the hard drive (slave disk) of the second IDE channel is identified as a HDB.
61. When the system administrator needs to upgrade the kernel version and change the system hardware configuration, the kernel should be recompiled.
62. If you only want to modify the system's IP address, you should modify the/etc/sysconfig/network-script/ifcfg-eth0 configuration file.
63. The/etc/hosts file should be configured when there are no conditions within the LAN to establish a DNS server, but you want users in the LAN to be able to access each other using the computer name.
64. In the VI editing environment, use the ESC key for mode conversion.
Slackware Linux 9.0 typically uses the Ext3 file system, and all of the system's disk blocks are made up of four parts.
66. Archive the/home/stud1/wang directory, compress it, generate the wang.tar.gz file, and save the file to the/home directory to implement the TAR command format for this task tar zcvf/home/wang.tar.gz/home/ Stud1/wang.
67. The pipeline is the standard output of the previous command as the normal input for the latter command.
68. When configuring a network using manual methods, you can change the hostname by modifying the/etc/hostname file, and to configure the domain name resolution client for that computer, configure the/etc/resolv.conf file.
69. The START process has two methods: Manual start and scheduled start, in which the command to start commonly used commands is at, batch, and crontab.
test.bns.com.cn domain name is bns.com.cn, if you want to configure a domain name server, you should define the working directory of the DNS database in the named.conf file.
The two main protocols used by the SendMail messaging system are SMTP and POP, which are used to send messages, which are used to receive messages.
A. DHCP is the short name of a Dynamic Host Configuration protocol that assigns an IP address to a host in the network.
73. There are many kinds of software packages used by proxy servers, and squid is used in textbooks.
The "rm" command deletes a file or directory, the main difference being whether to use the recursive switch-R or-R.
The. MV command allows you to move files and directories, and also to rename files and directories.
76. The hop count for the routing protocol (RIP) indicates the number of gateways that must pass before reaching the destination, and the longest distance that RIP accepts is 15 hops.
A. Ping command is used to test the connectivity of the network, and the ping command is implemented via the ICMP protocol.
The NFS protocol is used to implement file system sharing between UNIX (/linux) hosts.
79. In the Linux operating system, devices are accessed through special files.
The shell is not only an interpreter of user commands, it is also a powerful programming language. Bash is the default shell for Linux.
81. Use the >> symbol to append the output redirect content to the back of the original.
82. The command to add a user is: AddUser or Useradd.
83 for string lookups, use the grep command.
84. Use * to match several characters at a time.
The/sbin directory is used to store the hypervisor used by the system administrator.
Two Single-Choice questions:
1. In the following network protocol, the connection-oriented protocol is: A.
A Transmission Protocol B User Datagram Protocol C Internet Protocol D Inter-network Control Message Protocol
2. In the file system load parameters specified in the/etc/fstab file, the D parameter is typically used for mobile devices such as CD-ROM.
A defaults B SW C rw and RO D noauto
3. linux file permissions are 10 bits in length, divided into four segments, and the third paragraph represents C.
A file type B permissions for the file owner
C file Owner group permissions D other users ' permissions
4. Terminate the command and Operation B that a foreground process may use.
A kill B <ctrl>;+c C shut down D Halt
5. When you use the mkdir command to create a new directory, the option to create a parent directory when its parent directory does not exist is D.
A-m b-d c-f d-p
6. The following about the I node describes the error is a.
A I node and the file is one by one corresponding (each file has a unique index node number corresponding to it, but for an index node number, but can have more than one file name corresponding)
B I node can describe the number of blocks occupied by a file
The C I node describes the file size and pointers to the data block
D the transformation of the logical and physical structure of the file through the I node
7. A file name is RR. Z, the command that can be used to decompress is: D.
A tar B gzip C compress D uncompress
8. With a lot of C language functions, also known as the filter is C.
A CSH
B tcsh
C awk
D SED
9. A host to achieve over the LAN to communicate with another LAN, the job needs to do is C.
A Configure the name server
B defines a route that the local computer points to the same network
C defines a route that the local computer points to the network gateway that is located
D defines a route that is native to the destination network gateway
10. The file to be used to establish dynamic routing has D.
A/etc/hosts b/etc/hostname c/etc/resolv.conf D/etc/gateways
11. The network address of the LAN is 192.168.1.0/24, the gateway address of the local network connection to the other network is 192.168.1.1. When the host 192.168.1.20 accesses the 172.16.1.0/24 network, its routing is set correctly for B.
A Route add–net 192.168.1.0 GW 192.168.1.1 netmask 255.255.255.0 metric 1
B Route add–net 172.16.1.0 GW 192.168.1.1 netmask 255.255.255.0 metric 1
C Route add–net 172.16.1.0 GW 172.16.1.1 netmask 255.255.255.0 metric 1
D route add default 192.168.1.0 netmask 172.168.1.1 metric 1
12. In the following reference, D is not within the scope of the Ifconfig command.
A Configure the local loopback address B to configure the IP address of the NIC
C Activate the network adapter D load the NIC into the kernel
13. The following is a description of the link, the error is B.
A hard link is to have the I node of the link file point to the I node of the linked file
B hard links and symbolic connections are all generating a new I node
C links are broken into hard links and symbolic links D Hard connect cannot link catalog file
14. When a host in the local area network tests the network connection with the ping command, it is found that the host inside the network can be combined with the public network, and the problem may be C.
A host IP setting is incorrect
B no gateway to the LAN is set up
C LAN Gateway or host gateway is set incorrectly
D LAN DNS server settings are incorrect
15. In the following file, the file containing the mapping of the hostname to the IP address is: B.
A/etc/hostname b/etc/hosts c/etc/resolv.conf D/etc/networks
16. Do not need to compile the kernel is the case of D.
A remove the system without the device driver when B upgrades the kernel
C When adding new hardware, D activates the network card
17. There are four methods for assigning variables in the shell, in which the Name=12 method is called a.
A Direct Assignment b using the Read command
C use command-line parameter d to use the output of the command
The D command intercepts the data for the specified content from each line of the text file.
A CP B DD C FMT D cut
19. The following is not a Linux system process type D.
A process of interactive process B batch processing C daemon D ready process
20. Configure the Apache 1.3.19 server to modify the configuration file to ___a______
A httpd.conf B access.conf C srm.conf D named.conf
21. The subsystem that the kernel does not include is D. process, memory, I/O, file management system
A Process Management System B memory management system C I/O management System D hardware management system
22. In the daily management, the CPU usually affects the performance of the system is: A.
A CPU running at full load B CPU operating efficiency of 30%
C CPU operating efficiency of 50% D CPU operating efficiency of 80%
23. If the memory of a computer is 128MB, the size of the swap partition is usually C.
A 64MB B 128MB C 256MB D 512MB
24. The fifth step in installing Linux is to let the user choose how to install it, and if the user wants to install some of the components (software programs) and let the system install automatically after selecting it, the option that should be selected is D.
A full B expert C newbie D Menu
25. Linux has three commands to view files, if you want to view the contents of the file can be moved up and down to view the contents of the file, you should use the C command.
A Cat B More C less D menu
26. The following information is a running process that is listed by a system with the PS–EF command and the D process is running an Internet Super server that listens for connections on the Internet sockets and invokes the appropriate server to process the received information.
A Root 1 4.0 0.0 344 204? S 17:09 0:00 Init
B Root 2 0.0 0.1 2916 1520? S 17:09 0:00/sbin/getty
C Root 3 0.0 0.2 1364 632? S 17:09 0:00/USR/SBIN/SYSLOGD
D Root 4 0.0 1344 1204? S 17:09 0:10/usr/sbin/inetd
27. In the TCP/IP model, the application layer contains all the high-level protocols, and in some of the following application protocols, B is capable of implementing file transfers between local and remote hosts.
A telnet B FTP C SNMP D NFS
28. When we are not connected to a remote network, we need to track the route view in order to understand where there is a problem in the network, and the command that satisfies that purpose is C.
A Ping B ifconfig C traceroute D netstat
29. A file named Fido is modified with chmod 551 Fido, and its permission is D.
A-rwxr-xr-x b-rwxr--r--c-r--r--r--D-r-xr-x-x
30. In the Disk Address table in the I node table, if the length of a file is from block 1th to 11th of the disk Address table, the file occupies a total of B numbers.
A-B 266 C one D 256x10
31. The following list of files is listed with the Ls–al command, and the D file is a symbolic connection file.
A-rw-rw-rw-2 hel-s users, Sep 11:05 Hello
B-RWXRWXRWX 2 hel-s users, Sep 11:05 Goodbey
C drwxr--r--1 hel users Sep 08:10 Zhang
D lrwxr--r--1 Hel users 2024 Sep 08:12 Cheng
32. The DNS domain Name system is primarily responsible for parsing between host names and a.
A IP address B MAC address C network address D host Alias
33. WWW server is the most widely used on the Internet, it uses B structure.
A Server/Workstation B S/b C centralized D-distributed
34. The Linux system sends messages to other users via the C command.
A less B mesg y C write D Echo to
35. NFS is a C system.
A file B disk C Network file D operation
36. The D command can be used to perform file-to-tape backup work on Linux security systems.
A cp B tr C dir D cpio
37. The files of the Linux file system are placed in the relevant directory according to their functions, and in the case of external device files, they should be placed in the C directory.
A/bin b/etc C/dev D/lib
38. When you restart the Linux system and write the information in memory to the hard disk, you should use the D command.
A # reboot B # halt C # reboot D # shutdown–r now
39. Network management has the following major functions: Configuration management, A, performance management, security management and billing management.
A Fault Management B daily backup management C upgrade Management D Send mail
40. The description of the proxy server, the correct is a.
A Use an existing public proxy server on the Internet, just configure the client.
The B proxy server can only proxy client HTTP requests.
C a proxy server that is set up can be used by any host on the network.
D the client using a proxy server does not have its own IP address.
41. Turn off the Linux system (do not restart) to use command B.
A Ctrl+alt+del B Halt C shutdown-r now D reboot
42. The command to implement conversion from IP address to Ethernet MAC address is: C.
A Ping B ifconfig C arp D traceroute
43. In the vi Editor, in command mode, type B to add a new row under the current line of the cursor.
A <a>; B <o>; C <I>; D A
44. In the vi Editor, in command mode, delete the character at the current cursor using the A command.
A <x>; B <d>;<w>; C <D>; D <d>;<d>;
45. In the vi Editor, in command mode, repeat the last action you made on the edited text, using the C command.
A up ARROW B down ARROW C <.>; D <*>;
46. The description of the file FF is shown in the command ls-al as follows, so the file FF is of type A.
-rwxr-xr--1 root root 599 Cec 17:12 ff
Now use the Ls-l command to view a list of files in the details format, and you will see the following:
Total 5
Drwxr-x---4 user group 4096 Mar 00:37 filename
Drwxr-xr-x user group 4096 Mar 10 20:16 file name
-RW-------1 User group 524 Mar 00:40 A
-rw-r--r--1 user Group, June, B
DRWX------2 User group 4096 Mar 9 11:06 C
A total of seven columns of information are displayed, from left to right: permissions, number of files, attribution user, attribution group, file size, creation date, file name
One of the special things to note is the first column:
Drwxr-xr-x
A total of 10 locations, can be divided into 4 groups:
D rwx R-x R-x
The first group has only one character:
D folder
-Normal file
L Link
B-Block device files
P Pipeline File
C-Character device files
s set of interface files
The remaining 3 groups are attribution users, attribution groups, other users or groups of permissions for the file. We look at the format of it
RWX rwx rwx
R readable
W Writable
X executable
They cannot be reversed by the way, and a location that is empty (-) does not have the appropriate permissions.

A Plain file B hard link C directory D symbolic link
47. The Delete file command is: D.
A mkdir B rmdir C MV D RM
48. The following names do not belong to the DNS server type: ____c_____
A Primary master server B Secondary master server
C Samba D cache_only Server
49. Network administrators to the WWW server access, control access and operation of control, these controls can be reflected in A file.
A httpd.conf B lilo.conf C inetd.conf D resolv.conf
50. The mail forwarding agent, also known as the Mail forwarding server, can use the SMTP protocol or the C protocol.
A FTP B TCP C UUCP D POP
51. There are two ways to start the Samba server process: The standalone boot method and the parent process startup mode, where the former is started as a standalone process in the C file.
A/USR/SBIN/SMBD b/usr/sbin/nmbd C Rc.samba d/etc/inetd.conf
52. DHCP is the short name of a Dynamic Host Configuration Protocol, which enables network administrators to manage a network system through a single server, automatically assigning ___d______ addresses to hosts in a network.
A network B MAC C TCP D IP
53. To ensure that the DHCP process starts automatically when the server is started, you should change the Dhcpd=no in a file to Dhcpd=yes.
A rc.inet1 B lilo.conf C inetd.conf D httpd.conf
54. The command to archive the file is D.
A DD B cpio C gzip D tar
55. Change the file owner's command to C.
A chmod B Touch C chown D Cat
56. The command to find a string in the given file that matches the set criteria is: A.
A grep B gzip C Find D sort
57. To create a new file you can use the command for D.
A chmod B more C CP D touch
58. In the following command, the command that cannot display the contents of a text file is: D.
A more B less C tail D join
59. When using Anonymous Logon FTP, the user name is B.
A users B anonymous C root D guest
60. In practice, to understand the use of command logname, you can type D to get help.
A logname--man B logname/? C help logname D logname--help
61. If Lilo is installed in the MBR, use the A command to uninstall Lilo.
A lilo–u B lilo–c c lilo–v D lilo-v
62. When viewing files and directories with command Ls–al, to view the contents of a volume over the screen, use the key combination D.
A shift+home B Ctrl + PgUp C ALT + PgDn D shift+ PgUp
63. MC is UNIX-style operating system C.
A file Editor/program compiler B window tool for configuring the network
C Directory Browser/File Manager D Samba Server Administration Tool
64. The I node is a D-long table that contains information about the file.
A 8 byte B 16 byte C 32 bytes D 64 bytes
65. File permissions read, write, execute the three kinds of glyphs in turn is a.
A rwx B xrw C RDX D SRW
66. The length of a Linux file name must not exceed C characters.
A, B, C, D, 512.
67. There are three states of the process: C.
A readiness State, execution state and exit state B exact state, fuzzy state, and stochastic state
C run state, ready state and wait state D manual state, self-dynamic and Free State
68. To start a process from the background, add the symbol A at the end of the command.
A & B @ C # D $
69. B is not part of the messaging system.
A User Agent B Proxy Server C Transport agent D Delivery Agent
70. In a shell script, the command to read the contents of each field within a file and assign it to a shell variable is D.
A fold B Join C tr D Read
71. The crontab file consists of six fields, separated by a space between each domain, arranged as follows: B.
A MIN HOUR Day MONTH COMMAND
B MIN HOUR Day MONTH DAYOFWEEK COMMAND
C COMMAND HOUR Day MONTH DAYOFWEEK
D COMMAND Year MONTH day HOUR MIN
72. There are two modes of file transfer with ftp: C.
A Word and binary B. txt and word Document
C ASCII and binary D ASCII and rich Text Format
73. The permission of a member outside the group of a file is read-only, the owner has full permissions, and the permissions within the group are read and write, and the permission for the file is D.
A 467 B 674 C 476 D 764
74. When the DNS system is tested, the named process number is 53, and the command D notifies the process to reread the configuration file.
A KILL–USR2-B KILL–USR1-Kill-int kill–hup 53
75. Apache Server The default answer connection port number is C.
A 1024x768 B, C 8
76. The combined use of PHP and MySQL solved the C.
A handling of database access issues on proxy B dealing with hacker's illegal access problem on WWW server
C Handling database access issues on the WWW server
D Handling database access issues on the SendMail mail system
77. OpenSSL is an A.
A encryption Software B mail system C database management system D embedded scripting programming language
78. The configuration file for the Samba server is D.
A httpd.conf B inetd.conf C Rc.samba D smb.conf
79. About DNS servers, the description is correct for D.
A DNS server configuration does not require client configuration
B when establishing a DNS server for a partition, you only need to establish a primary DNS server
C the primary DNS server needs to start the named process, and the secondary DNS server does not require
The Root.cache file for the D DNS server contains information about the root name server
80. To exit the interactive mode of the shell, type C.
A <Esc>; B ^q C exit D quit