Free LPI 101-500 Practice Exam with Questions & Answers

The timeout option in a GRUB Legacy configuration file is used to define the amount of time (in seconds) that the GRUB menu will be shown to the user before booting the default entry. The timeout option is usually located in the /boot/grub/menu.lst file. For example, timeout 10 will display the GRUB menu for 10 seconds. To disable the timeout and wait for user input indefinitely, the value of timeout can be set to -1. To boot immediately without displaying the menu, the value of timeout can be set to 0. The other options are not valid for the GRUB Legacy configuration file. References:

GRUB Legacy - ArchWiki

How do I set the grub timeout and the grub default boot entry?

How to Remove the Timeout From GRUB Menu

The command that will reduce all consecutive spaces down to a single space is tr -s ’ ’ < a.txt > b.txt. This command uses the following options and syntax:

-s: Squeezes repeated characters listed in the first set with single occurrence.

’ ': Specifies a space character as the first set.

< a.txt: Redirects the input from a file named a.txt.

b.txt: Redirects the output to a file named b.txt.

The output of this command will be a new file called b.txt that contains the same text as a.txt, except that any sequence of multiple spaces will be replaced by a single space. For example, if the file a.txt contains the following text:

This is a text file with multiple spaces.

The file b.txt will contain the following text:

This is a text file with multiple spaces.

The other commands are incorrect for the following reasons:

A. tr ‘\s’ ’ ’ < a.txt > b.txt: This command will replace every whitespace character (\s) with a space character, which will not reduce the number of spaces, but rather convert tabs and newlines into spaces.

B. tr -c ’ ’ < a.txt > b.txt: This command will complement the first set, meaning that it will apply the operation to all characters that are not spaces. This will not affect the spaces at all, but rather squeeze all other characters.

C. tr -d ’ ’ < a.txt > b.txt: This command will delete all spaces from the input, which will not reduce them to a single space, but rather remove them completely.

D. tr -r ’ ’ ‘\n’ < a.txt > b.txt: This command will replace all spaces with newlines, which will not reduce the spaces, but rather create a new line for each word.

The bg command is used to move and resume in the background the last stopped shell job. A stopped job is a process that has been suspended by using Ctrl+Z or the kill -STOP command. The bg command will resume the execution of the stopped job and allow it to run in the background, without blocking the current shell. The bg command can also take a job number as an argument, which can be obtained by using the jobs command. For example, if the last stopped job is 1+ Stopped sleep 500, then the following command will move and resume it in the background:

bg %1

The output will be:

1+ sleep 500 &

The fg command is used to move and resume in the foreground the last stopped or backgrounded job. The run and back commands are not valid commands in Linux. References:

[LPI Exam 101 Detailed Objectives], Topic 103: GNU and Unix Commands, Objective 103.5: Create, monitor and kill processes, Weight: 4, Key Knowledge Areas: Use of jobs, fg and bg commands.

Linux Commands: jobs, bg, and fg, Topic: The bg Command.

The default nice level when a process is started using the nice command is 10. This means that the process will have a lower priority than the normal processes, which have a nice level of 0. The nice command allows the user to adjust the priority of a process at the time of its execution. The syntax of the nice command is:

nice [-n {nice value increment}] [command]

The -n option specifies the nice value increment, which can be a positive or negative integer in the range of -20 to 19. The command is the name of the program or script to be executed. If the -n option is omitted, the default nice value increment is 10. For example, the following command will run the program ackermann with a nice value of 10:

nice ./ackermann

To verify the nice value of a running process, we can use the ps or top commands and look at the NI column. For example, the following command will show the nice value of the ackermann process:

ps -el | grep ackermann

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)

 When using rpm --verify to check files created during the installation of RPM packages, the following information is taken into consideration:

Timestamps. RPM compares the modification time of the installed files with the original time stored in the RPM database. If the file has been modified after installation, the timestamp will differ and RPM will report it with an M flag1.

MD5 checksums. RPM calculates the MD5 checksum of the installed files and compares it with the original checksum stored in the RPM database. If the file has been altered in any way, the checksum will differ and RPM will report it with an 5 flag1.

File sizes. RPM compares the size of the installed files with the original size stored in the RPM database. If the file has been truncated or appended, the size will differ and RPM will report it with an S flag1.

RPM does not take into consideration the following information:

Inodes. RPM does not check the inode number of the installed files, as it is not a reliable indicator of file identity. The inode number can change if the file is moved, copied, or restored from a backup2.

GnuPG signatures. RPM does not verify the GnuPG signatures of the installed files, as they are not part of the RPM package format. The GnuPG signatures are used to verify the authenticity and integrity of the RPM package files before installation, not after3.

The command mount -a mounts all filesystems that are listed in the file /etc/fstab and have the option auto set. The option auto means that the filesystem can be mounted automatically by the mount -a command or at boot time. The option noauto means that the filesystem can only be mounted explicitly by the mount command with the device or mount point specified12. The file /etc/fstab contains information about the filesystems that are known to the system and how they can be mounted3. The command mount -a is useful for mounting all the filesystems that are needed by the system after a change in /etc/fstab or after a reboot4. References: 1: mount(8) - Linux man page 2: Linux mount and umount commands help and examples 3: fstab(5) - Linux man page 4: How to Use the mount Command on Linux

The file /proc/mounts contains a list of all currently mounted devices in the system. It is a pseudo-file that is dynamically generated by the kernel and reflects the actual state of the mount table. It has a similar format to /etc/fstab, but shows the actual mount options and file system types used by the kernel. The file /proc/mounts can be read by any user, but only the root user can modify it. The file /proc/mounts is also known as /proc/self/mounts, which is a symbolic link to the mounts file for the current process. References:

Understanding the /proc/mounts, /etc/mtab and /proc/partitions files

How to get the complete and exact list of mounted filesystems in Linux?

The /proc Filesystem

Pressing the Ctrl-C combination on the keyboard while a command is executing in the foreground sends the SIGINT(2) signal code. The SIGINT(2) signal means interrupt and is usually sent when the user presses Ctrl-C on the keyboard. The signal causes the process to terminate, unless it is caught or ignored by the process. The SIGHUP(1) signal means hang up and is usually sent when the terminal or network connection is disconnected. The SIGQUIT(3) signal means quit and is usually sent when the user presses Ctrl-\ on the keyboard. The SIGKILL(9) signal means kill and is used to force the process to terminate immediately, without any chance to catch the signal or perform any cleanup. The SIGTERM(15) signal means terminate and is the default signal sent by the kill command. References: LPI Exam 101 Detailed Objectives, Topic 103: GNU and Unix Commands, Weight: 25, Objective 103.3: Perform basic file management, Signal List

 The vi editor is a text editor that operates in two modes: command mode and insert mode. In command mode, the user can enter commands to perform various operations on the text, such as copying, pasting, deleting, moving, searching, etc. In insert mode, the user can type text into the file. To switch from command mode to insert mode, the user can press i, a, o, or other keys. To switch from insert mode to command mode, the user can press Esc. The yy command is used to copy (yank) the current line into a buffer. The number before the yy command specifies how many lines to copy, starting from the current line. Therefore, the command 17yy will copy the current line and the following 16 lines (17 lines total) into a buffer. The buffer can then be pasted into another location by using the p or P command. Note that the command 17yy does not paste the copied lines, it only copies them. References:

LPI 101-500 Exam Objectives, Topic 103.8, Weight 4

LPI Learning Materials, Chapter 3.8, Advanced Scripting

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