LPI Updated 101-500 Exam Questions and Answers by ronald

The p command in vi inserts the content of the buffer below the current line. The buffer is where the deleted or yanked text is stored temporarily. The P command inserts the buffer above the current line. The i command enters the insert mode before the cursor position. The U command restores the current line to its original state. The u command undoes the last change made to the file. References:

• [LPI Linux Essentials - 1.3 Basic Editing]
• [LPI Linux Essentials - 1.4 I/O Redirection]
• [LPI Linux Essentials - 1.5 Manage Simple Partitions and Filesystems]

In the vi editor, one of the ways to issue commands multiple times or apply them to multiple rows is to specify the number right in front of a command. This will repeat the command as many times as the number indicates. For example, the command 4l will move the cursor four characters to the right, and the command 2yj will copy two lines from the current line to the buffer. This method can be used for most of the vi commands that operate on single characters, words, lines, or blocks of text. Another way to issue commands multiple times or apply them to multiple rows is to use the . (dot) command, which repeats the last command. For example, after deleting a line with dd, pressing . will delete another line. However, this method is less precise and efficient than specifying the number before the command. References:

• Basic vi commands (cheat sheet), Topic: Moving within a File (Navigation).
• Vi Editor with Commands in Linux/Unix Tutorial, Topic: VI Editing commands.

The signal that is missing from the following command that is commonly used to instruct a daemon to reinitialize itself, including reading configuration files, is SIGHUP. The command should be:

kill -HUP pid

The option -HUP specifies the signal to be sent to the process, which is the hangup signal (SIGHUP). This signal is traditionally used to notify a process that the controlling terminal has been closed, but it is also commonly used to instruct a daemon to reinitialize itself, such as reloading its configuration files or reopening its log files. The argument pid is the process ID of the daemon to be reinitialized. For example, to reinitialize the nginx web server daemon with the PID 1234, the command would be:

kill -HUP 1234

This will cause the nginx daemon to reload its configuration files and gracefully restart its worker processes1. The other signals are not commonly used for this purpose, as they have different meanings and effects. For example, SIGTERM requests the process to terminate gracefully, SIGKILL forces the process to terminate immediately, SIGSTOP suspends the process, and SIGCONT resumes the process2. References:

• Controlling nginx — nginx 1.21.3 documentation
• Linux Signals - GeeksforGeeks

The command dd can be used to create a USB storage media from a disk image. The command dd is a low-level utility that can copy and convert data from one source to another, such as files, devices, or pipes. It can be used to create a bootable USB drive from an ISO image or a raw disk image. The syntax is: dd if=input of=output [options]. For example, to create a USB storage media from a disk image file named linux.img, the command would be:

dd if=linux.img of=/dev/sdb

This will copy the contents of linux.img to the device /dev/sdb, which is assumed to be the USB drive. The device name may vary depending on the system, so it is important to check the correct device name beforerunning the command. The command dd can also accept various options, such as bs to specify the block size, status to show the progress, or conv to apply conversions to the data. For example, to create a USB storage media from an ISO image file named linux.iso, with a block size of 4 MB and a progress indicator, the command would be:

dd if=linux.iso of=/dev/sdb bs=4M status=progress

The command dd is also known as "disk destroyer" because it can overwrite data without warning or confirmation. Therefore, it is advisable to use it with caution and backup any important data before using it. The other options are not correct because:

• gdisk is a command to create and manipulate GUID partition tables (GPT), but it does not create a USB storage media from a disk image1.
• cc is a command to compile C programs, but it does not create a USB storage media from a disk image2.
• fdisk is a command to create and manipulate DOS partition tables, but it does not create a USB storage media from a disk image3.
• mount is a command to mount file systems, but it does not create a USB storage media from a disk image4. References:
• How to Create a Bootable Linux USB Flash Drive, the Easy Way
• dd(1) — Linux manual page
• How to use the dd command in Linux - TechRepublic
• LPI Exam 101 Detailed Objectives, section 1.101.3