Free Practice Questions for LPI 101-500 Exam

The reserved space is a portion of the filesystem that is only accessible to the root user or users with sudo privileges. The reserved space serves two purposes: to prevent ordinary users from filling up the filesystem completely and crashing the system, and to reduce fragmentation by leaving some free space. The reserved space is set by default to 5% of the total filesystem size when the filesystem is created with the mkfs.ext4 command. This means that 5% of the blocks are reserved for the root user and are not counted as available space by the df command. The reserved space can be changed or disabled by using the tune2fs command with the -m option. For example, to change the reserved space to 1%, use the following command:

sudo tune2fs -m 1 /dev/sdXY

where /dev/sdXY is the device name of the ext4 filesystem.

To disable the reserved space completely, use 0% instead of 1%. However, this is not recommended, as it may affect the performance and stability of the system, especially if the filesystem is almost full.

The command that uninstalls a package but keeps its configuration files in case the package is re-installed is dpkg -r pkgname. The dpkg command is the low-level tool for installing, building, removing, and managing Debian packages. The -r or --remove option removes an installed package from the system, but it does not delete the configuration files and other data that belong to the package. This way, if the package is re-installed later, the previous settings are preserved. The dpkg command is part of the 101.1 Determine and configure hardware settings topic of the LPI Linux Essentials certification program12.

The other options are either invalid or do not perform the desired task. The dpkg -s pkgname command shows the status of an installed package, but it does not uninstall it. The dpkg -L pkgname command lists the files that belong to an installed package, but it does not uninstall it. The dpkg -P pkgname command purges an installed or removed package, which means it deletes the configuration files and other data that belong to the package. The dpkg -v pkgname command shows the version of an installed package, but it does not uninstall it.

The correct command to change the number of days before the ext3 filesystem on /dev/sda1 has to run through a full filesystem check while booting is tune2fs -i 200 /dev/sda1. This command sets the interval between two filesystem checks to 200 days. The tune2fs command allows you to view and change various filesystem parameters on Linux ext2, ext3, or ext4 filesystems. The -i option specifies the time interval between checks. The other options are incorrect because they use the wrong parameters for the tune2fs command. Option A is wrong because the -d option is not supported by the tune2fs command. Option B is wrong because the -c option sets the maximum number of mounts, not days, before a check. Option D is wrong because the -n option is not supported by the tune2fs command. Option E is wrong because the --days option is not supported by the tune2fs command. References:

[LPI Linux Essentials - 2.2 Mounting, Unmounting Filesystems]

15 tune2fs command examples in Linux [Cheat Sheet] - GoLinuxCloud

Linux tune2fs command With Examples - GeeksforGeeks

tune2fs command-file system management - Linuxstar

tune2fs Command Examples - Gianforte School of Computing

The permissions -rwSr-xr-x mean that the file is readable and writable by the owner, readable and executable by the group, and readable and executable by others. The S in the owner’s permissions indicates that the file has the SetUID bit set, which means that when the file is executed as a command, it will run with the effective user ID of the file owner, rather than the user who executed it. This allows the command to perform privileged operations that the user normally cannot do. For example, the /bin/passwd command has the SetUID bit set, so that it can modify the /etc/shadow file, which is only writable by root. References: LPI Linux Administrator, File Permissions and Attributes

The correct command to locate programs and their corresponding man pages and configuration files is whereis. The whereis command searches for the binary, source, and manual files for a given command name in a list of standard Linux directories. It can also accept a list of directories to search in by using the -B, -M, or -S options. The whereis command is useful for finding the location and documentation of a program. The other commands are not suitable for this task. The dirname command strips the last component from a file name and returns the directory name. The which command shows the full path of a command that is in the $PATH variable. The basename command strips the directory and suffix from a file name and returns the base name. The query command is not a standard Linux command. References:

[LPI Linux Essentials - 1.1 The Linux Community and a Career in Open Source]

[LPI Linux Essentials - 1.2 Finding Your Way on a Linux System]

[LPI Linux Essentials - 1.4 Finding Files]

whereis command in Linux with Examples - GeeksforGeeks

Whereis Command in Linux | Linuxize

Linux whereis Command Explained for Beginners (5 Examples) - HowtoForge

whereis command | Linux# - Geek University

whereis command in Linux - LinuxForDevices