Pass the LPIC Level 1 101-500 Questions and answers with ExamsMirror

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.

∗∗Thegrepcommandthatwillprintonlythelinesthatdonotendwitha/inthefilefooisgrep−v′/’ foo. This command uses the following options and pattern:

-v: Inverts the matching, meaning that it only outputs the lines that do not match the pattern. /:Matchesa/characterattheendofaline.The symbol represents the end of a line in regular expressions. foo: The name of the file to search.

The output of this command will show all the lines in the file foo that do not have a / as the last character. For example, if the file foo contains the following lines:

/home/user/ /var/log/messages /etc/passwd /usr/bin/

The output of the command will be:

/var/log/messages /etc/passwd

The other commands are incorrect for the following reasons:

grep ‘/$’ foo: This command will print only the lines that do end with a / in the file foo, which is the opposite of what is required.

grep ‘/#’ foo: This command will print only the lines that contain the string /# in the file foo, which is not related to the question.

grep -v ‘/#’ foo: This command will print only the lines that do not contain the string /# in the file foo, which is also not related to the question.

References:

[LPI Exam 101 Detailed Objectives], Topic 103: GNU and Unix Commands, Objective 103.7: Perform basic file management, Weight: 4, Key Knowledge Areas: Use ofegrepto search for extended regular expressions in text output.

[How to Use the grep Command on Linux], Topic: Start and End of Lines.

A hard link is a directory entry that refers to the same inode as another file. An inode is a data structure that stores the metadata and the location of the data blocks of a file. A hard link allows multiple names to refer to the same file content, as long as they are on the same filesystem. However, if the source and the target of the hard link are on different filesystems, the ln command will return an error, because the inode numbers are not consistent across different filesystems. Therefore, the ln command cannot create a hard link that crosses filesystem boundaries. The other options are either incorrect or not applicable. The source file being hidden, read-only, a shell script, or not owned by the user does not prevent the creation of a hard link, as long as the user has the permission to write to the target directory and the source and the target are on the same filesystem. References:

LPIC-1 Exam 101 Objectives, Topic 103: GNU and Unix Commands, 103.3 Perform basic file management

LPIC-1 Linux Administrator 101-500 Exam FAQ, LPIC-1 Exam 101 Objectives, GNU and Unix Commands (Total Weight: 25)

The maximum niceness value that a regular user can assign to a process with the nice command when executing a new process is 19. The niceness value is a user-space value that controls the priority of a process. The lower the niceness value, the higher the priority, and vice versa. The niceness value range is -20 to +19, where -20 is the highest priority and +19 is the lowest priority. The default niceness value is 0. The nice command can be used to run a new process with a modified niceness value. The syntax is: nice -n value command, where value is the niceness value and command is the process to run. For example, nice -n 10 sleep 60 will run the sleep command with a niceness value of 10 for 60 seconds. However, regular users can only increase the niceness value of their processes, not decrease it. This means that they can only lower the priority of their processes, not raise it. The minimum niceness value that a regular user can assign is 0, and the maximum is 19. Only the root user can assign a negative niceness value, which means raising the priority of a process. For example, nice -n -10 sleep 60 will run the sleep command with a niceness value of -10 for 60 seconds, but only if the user is root. The other options are not correct because:

A. 9 is not the maximum niceness value that a regular user can assign, but a valid niceness value within the range.

C. 49 is not a valid niceness value, as it exceeds the maximum of 19.

D. 99 is not a valid niceness value, as it exceeds the maximum of 19.

 Running a command in the background of your shell means that the command will execute asynchronously, without blocking the shell prompt or waiting for user input. This can be useful for commands that take a long time to complete, or that do not require user interaction. One of the valid reasons to run a command in the background is when the command has to run immediately but the user needs to log out. For example, if the user wants to start a backup process that will take several hours, but also wants to close the terminal session and log out from the system, they can run the backup command in the background by appending an ampersand (&) to the command line. This way, the backup command will continue to run even after the user logs out, and the user can check the status or output of the command later. The other options are either incorrect or not applicable. Running a command in the background does not affect the execution priority of the command, which is determined by the nice value and the scheduler. Running a command in the background does not delay the execution of the command, which will start as soon as possible. Running a command in the background does not guarantee that the command will survive a system shutdown or reboot, unless the command is configured to do so with a service manager or a startup script. References:

LPIC-1 Exam 101 Objectives, Topic 103: GNU and Unix Commands, 103.1 Work on the command line

LPIC-1 Linux Administrator 101-500 Exam FAQ, LPIC-1 Exam 101 Objectives, GNU and Unix Commands (Total Weight: 25)

The /etc/mtab file is a system-generated file that lists all the currently mounted devices and their mount options. It is updated automatically by the mount and umount commands. It can be used to check which devices are mounted and where, as well as their filesystem type and mount options. The /etc/mtab file hasthe same format as the /etc/fstab file, which is a user-edited file that lists the devices that should be mounted at boot time or on demand. References:

LPIC-1 Exam 101 Objectives, Topic 101: System Architecture, 101.1 Determine and configure hardware settings, Key Knowledge Areas, The following is a partial list of the used files, terms and utilities: /etc/mtab

LPIC-1 101-500 Exam Prep, Section 1: System Architecture, Lesson 1.1: Determine and Configure Hardware Settings, Video: 1.1.4 Mounting and Unmounting Filesystems, Transcript: The /etc/mtab file is a system-generated file that lists all the currently mounted devices and their mount options.

 The tail command prints the last part of a file to the standard output. The -n option specifies the number of lines to print. Therefore, tail -n 10 filename will print the last 10 lines of the file named filename. The other commands are either invalid or do not perform the desired task. The cat command concatenates files and prints them to the standard output, but it does not have a -n option. The dump command is used to backup filesystems, not to print files. The head command prints the first part of a file, not the last part. References:

LPIC-1 Exam 101 Objectives, Topic 103: GNU and Unix Commands, 103.3 Perform basic file management

LPIC-1 Linux Administrator 101-500 Exam FAQ, LPIC-1 Exam 101 Objectives, GNU and Unix Commands (Total Weight: 25)

The file command determines the type of a file by using a definition database file which contains information about all common file types. The database file is usually located at /usr/share/misc/magic or /usr/share/file/magic and can be customized by the user. The file command analyzes the content and structure of the file and compares it with the patterns in the database file to identify the file type. The file command can also check the file name extension, but it does not rely on it. The other options are either invalid or do not perform the desired task.The magic, pmagic and hash commands are not valid Linux commands. The type command is used to display information about command type, not file type. References:

LPIC-1 Exam 101 Objectives, Topic 103: GNU and Unix Commands, 103.3 Perform basic file management

LPIC-1 Linux Administrator 101-500 Exam FAQ, LPIC-1 Exam 101 Objectives, GNU and Unix Commands (Total Weight: 25)

The cut command is used to extract sections from each line of a file or input stream. The -d option specifies the delimiter that separates the fields in each line. The -f option specifies the fields to select. In this case, the delimiter is a colon (:) and the fields are 1 and 7. The first field is the user name and the seventh field is the login shell. Therefore, the cut command with these options will generate a list of user names and their login shells from /etc/passwd. References:

Linux cut Command Explained with 6 Examples

How to Use the Linux cut Command

cut command in Linux with examples

In Bash, inserting 1>&2 after a command redirects standard output to standard error. This means that the output of the command that normally goes to the standard output stream (file descriptor 1) will be sent to the standard error stream (file descriptor 2) instead. This can be useful if we want to capture or discard both the normal output and the error output of a command. For example, if we want to run a command and send both its output and error to /dev/null (a special device that discards any data written to it), we can use:

command > /dev/null 1>&2

This will redirect the standard output of command to /dev/null, and then redirect the standard error of command to the same place as the standard output, which is /dev/null. The other options are not correct because:

A. standard error to standard input: This is not possible, because standard input is a read-only stream, and we cannot redirect output to it.

B. standard input to standard error: This is not what 1>&2 does, because 1 refers to standard output, not standard input. To redirect standard input to standard error, we would need to use 0>&2, where 0 refers to standard input.

D. standard error to standard output: This is not what 1>&2 does, because it would require the opposite order of file descriptors: 2>&1. This would redirect standard error to standard output, not the other way around.

E. standard output to standard input: This is not possible, for the same reason as option A. References:

Bash redirections cheat sheet

How to redirect stderr to a file - Linuxize