Most Recent LPI 102-500 Exam Dumps

The correct SQL query to count the number of occurrences for each value of the field order_type in the table orders is:

SELECT order_type,COUNT(*) FROM orders GROUP BY order_type;

This query uses theSELECTstatement to retrieve the values of the order_type field and theCOUNT(*)function to count the number of rows for each order_type. TheGROUP BYclause groups the rows by the order_type field, so that the count is calculated for each distinct value of order_type. The result of this query is a table with two columns: order_type and count, where each row shows the number of orders for a specific order_type.

The other options are incorrect for the following reasons:

A: This query uses aWHEREclause that is always true, since order_type=order_type for every row. Therefore, this query returns the same result asSELECT order_type,COUNT(*) FROM orders;, which is a table with one row that shows the total number of orders, regardless of the order_type.

C: This query is syntactically invalid, since theCOUNTfunction cannot take a subquery as an argument. The correct way to use a subquery withCOUNTisCOUNT((SELECT order_type FROM orders));, which returns the total number of orders, regardless of the order_type.

D: This query uses theORDER BYclause to sort the rows by the order_type field, but it does not group them by order_type. Therefore, this query returns the same result asSELECT COUNT(*) FROM orders;, which is a table with one row that shows the total number of orders, regardless of the order_type.

E: This query is syntactically invalid, since there is no such function asAUTO_COUNTin SQL, and theCOUNTfunction cannot take a field name as an argument. The correct way to useCOUNTwith a field name isCOUNT(order_type);, which returns the number of non-null values in the order_type field.

[SQL COUNT Function]

[SQL GROUP BY Statement]

[SQL SELECT Statement]

The command that must be run in order to ensure the MTA knows about the new email alias is:

newaliases

This command updates the MTA's aliases database and makes the changes effective.It is equivalent to the commandssendmail -biorsendmail -I12.The newaliases command should be run after making modifications to the /etc/aliases file, which contains the email aliases for the system3.

The statement hosts: files dns is valid in the file /etc/nsswitch.conf. It means that the system will use the local /etc/hosts file and the Domain Name System (DNS) to resolve host names to IP addresses. The order of the sources on the line determines the order in which they will be queried. In this case, the system will first check the /etc/hosts file for a matching host name, and if not found, it will query the DNS servers configured in /etc/resolv.conf. The other statements in the question are not valid in the /etc/nsswitch.conf file. The statement multi on is not a valid keyword or source for any database. The statement 192.168.168.4 dns-server is not a valid syntax for specifying a source or an action. The statement include /etc/nsswitch.d/ is not a valid way to include another file or directory in the /etc/nsswitch.conf file.Reference:

[LPI Linux Administrator - Exam 102 Objectives - Topic 109: Networking Fundamentals]

nsswitch.conf(5) - Linux manual page

What is the /etc/nsswitch.conf file in Linux -- TecAdmin

The command ifconfig can be used to set a network interface active or inactive by using the up or down options. For example, the following command will activate the eth0 interface:

sudo ifconfig eth0 up

The command ifconfig can also be used to change the netmask used on a network interface by specifying the netmask option followed by the desired netmask value. For example, the following command will change the netmask of the eth0 interface to 255.255.255.0:

sudo ifconfig eth0 netmask 255.255.255.0

The other options in the question are not possible with the ifconfig command. The command ifconfig cannot specify the kernel module to be used with a network interface. This is done by the modprobe command or the /etc/modules file. The command ifconfig cannot allow regular users to change the network configuration of a network interface. This is controlled by the sudoers file or the polkit framework. The command ifconfig cannot specify which network services are available on a network interface. This is done by the firewall rules or the /etc/services file.Reference:

[LPI Linux Administrator - Exam 102 Objectives - Topic 109: Networking Fundamentals]

Linux ifconfig Command | Linuxize

15 Useful ''ifconfig'' Commands to Configure Network in Linux - Tecmint

ifconfig command in Linux with Examples - GeeksforGeeks

The nmcli command is a command-line interface for NetworkManager, which is a tool for configuring and managing network settings on Linux systems. The nmcli command consists of different subcommands that correspond to different aspects of network configuration and management. The subcommands are:

nmcli general: shows status and permissions of NetworkManager, as well as system hostname and logging level and domains.

nmcli connection: enables you to create, modify, activate, deactivate, delete, and show network connections.

nmcli device: enables you to show, modify, and control network devices, such as interfaces, bonds, teams, bridges, etc.

nmcli monitor: monitors activity of NetworkManager and watches for changes in the state of connectivity and devices.

nmcli networking: enables or disables overall networking.

nmcli radio: enables or disables radio transmitters for Wi-Fi, Bluetooth, and WWAN devices.

nmcli agent: registers as a secret agent that provides and caches network credentials.

The other options listed are not valid nmcli subcommands. There is no nmcli ethernet, nmcli wifi, or nmcli address subcommand. However, nmcli device and nmcli connection can be used to configure and manage Ethernet and Wi-Fi connections and addresses.Reference:

NetworkManager configuration and usage | SLE Micro 5.3

nmcli: NetworkManager Reference Manual - GNOME

nmcli: command not found -- The Geek Diary