101-500 Exam Dumps - LPIC Level 1 Questions and Answers

 The RPM command that will output the name of the package which supplied the file /etc/exports is rpm -qf /etc/exports. This command will query the RPM database and find the package that owns or provides the file /etc/exports1. The output will show the package name, version, release, and architecture. For example:

The other options are incorrect for the following reasons:

• rpm -F /etc/exports. This command will try to freshen or upgrade the package that contains the file /etc/exports, if it is already installed2. This command will not output the package name, but rather install the latest version of the package from a specified source. For example:

• rpm -Kl /etc/exports. This command is not valid, as RPM does not have a -Kl option. The -K option is used to verify the signatures of the RPM package files, not the installed files3. The -l option is used to list the files in a package, not to query the package name. For example:

• rpm -qp /etc/exports. This command will try to query the package information of the file /etc/exports, as if it was an RPM package file. This command will not output the package name, but rather an error message, as /etc/exports is not a valid RPM package file. For example:

• rpm -qi /etc/exports. This command will try to query the information of the package /etc/exports, as if it was an installed package name. This command will not output the package name, but rather an error message, as /etc/exports is not a valid package name. For example:

References:

• How to find which rpm package provides a specific file or library in RHEL / CentOS
• rpm(8) - Linux manual page
• rpm(8) - Linux manual page
• [rpm(8) - Linux manual page]

The /etc/apt/sources.list file is the main configuration file for the Advanced Package Tool (apt), which is used to manage Debian installation package files. This file contains a list of repositories, or sources, from which apt can download and install packages. Each repository is specified by a line that has the following format:

type uri suite [component1] [component2] […]

Where:

• type is the access method, such as http, ftp, file, etc.
• uri is the Uniform Resource Identifier (URI) of the repository, such as http://deb.debian.org/debian
• suite is the distribution code name or archive name, such as stable, testing, unstable, etc.
• component is an optional section of the repository, such as main, contrib, non-free, etc.

For example, a typical sources.list file for Debian stable could look like this:

deb http://deb.debian.org/debian stable main contrib non-free deb-src http://deb.debian.org/debian stable main contrib non-free

deb http://deb.debian.org/debian-security/ stable/updates main contrib non-free deb-src http://deb.debian.org/debian-security/ stable/updates main contrib non-free

deb http://deb.debian.org/debian stable-updates main contrib non-free deb-src http://deb.debian.org/debian stable-updates main contrib non-free

The first two lines specify the main repository for Debian stable, with both binary (deb) and source (deb-src) packages. The next two lines specify the security updates repository for Debian stable, which contains important security fixes. The last two lines specify the stable-updates repository, which contains packages that have been updated after the release of Debian stable.

By editing the /etc/apt/sources.list file, one can select the network locations from which Debian installation package files are loaded. However, it is recommended to use a graphical or command-line tool, such as aptitude or synaptic, to manage the sources.list file, as they can handle the syntax and avoid errors.

References:

• 1, 102.4 Lesson 1
• 2, 102.4 Use Debian package management
• man sources.list

The command that is used to update the list of available packages when using dpkg based package management is apt-get update12. The apt-get command is a high-level tool that works with dpkg and provides a user-friendly interface for managing packages3. The apt-get update command is used to synchronize the package index files from the sources specified in the /etc/apt/sources.list file12. This command does not install or upgrade any packages, but only downloads the information about the latest versions and dependencies of the packages12. The apt-get update command is usually run before the apt-get upgrade or apt-get install commands, which are used to upgrade or install packages respectively12.

The other options in the question are not correct because:

• B. apt-get upgrade: This command is used to upgrade the installed packages to the latest versions, not to update the list of available packages12.
• C. apt-cache update: There is no such command in Linux. The apt-cache command is used to query and display information about the packages, not to update them4.
• D. apt-get refresh: There is no such command in Linux. The closest command is apt-get update, which is the correct answer.
• E. apt-cache upgrade: There is no such command in Linux. The closest command is apt-get upgrade, which is not the correct answer.

References:

1: How To Manage Packages Using apt-get, apt-cache, apt-file and dpkg Commands In Debian Based Systems 2: Ubuntu Manpage: apt-get - APT package handling utility – command-line interface 3: dpkg - Debian Wiki 4: Ubuntu Manpage: apt-cache - query the APT cache

 The dpkg-reconfigure command is used to reconfigure an already installed package. It asks configuration questions for the package, just as if the package were being installed for the first time. This can be useful if the user wants to change some settings or options for the package without reinstalling it. The dpkg-reconfigure command can also be used to fix a broken package configuration or to restore the default settings. References:

• dpkg-reconfigure(8) - Linux man page
• Linux Professional Institute: Exam 101 Objectives

The environment variable that overrides or extends the list of directories holding shared libraries is LD_LIBRARY_PATH. This variable is used to specify a colon-separated list of directories where the dynamic linker should look for shared libraries when loading a program1. The directories in LD_LIBRARY_PATH are searched before the default directories, such as /lib and /usr/lib, or the directories specified in/etc/ld.so.conf or the executable’s rpath1. This variable can be useful for testing or debugging purposes, or for running programs that require a specific version of a library that is not installed in the system1.

The other options are incorrect for the following reasons:

• LD_LOAD_PATH. This is not a standard environment variable for shared libraries. It may be confused with LD_PRELOAD, which is a variable that allows the user to specify one or more shared libraries that should be loaded before any other library, even the C library2. This variable can be used to override or modify the behavior of certain functions or symbols in the libraries2.
• LD_LIB_PATH. This is not a standard environment variable for shared libraries. It may be confused with LIBPATH, which is a variable that is used on some Unix variants, such as AIX, to specify the search path for shared libraries3. On Linux, this variable has no effect4.
• LD_SHARE_PATH. This is not a standard environment variable for shared libraries. It may be confused with LD_RUN_PATH, which is a variable that allows the user to specify a list of directories that should be embedded in the executable as the rpath5. The rpath is a attribute that tells the dynamiclinker where to look for shared libraries at run time5. Unlike LD_LIBRARY_PATH, LD_RUN_PATH is only effective at link time, not at run time5.
• LD_RUN_PATH. This is not an environment variable that overrides or extends the list of directories holding shared libraries, but rather one that sets the rpath of the executable at link time. See the explanation for LD_SHARE_PATH above.

References:

• How to set the environmental variable LD_LIBRARY_PATH in Linux
• LD_PRELOAD - The secret of code injection into a running process without ptrace
• LIBPATH - Wikipedia
• linux - What is the difference between LD_LIBRARY_PATH and -L at link time? - Stack Overflow
• ld-linux(8) - Linux manual page

The /tmp directory should be on a separate partition if possible because it is world writable. This means that any user can create, modify, or delete files and directories in /tmp. This can pose a risk of filling up the / partition, which can cause system instability or failure. By having /tmp on a separate partition, we can limit the amount of disk space that can be used by temporary files and prevent users from affecting the / partition. The /tmp directory is also a common target for malicious attacks, so having it on a separate partition can improve the security and isolation of the system. The /tmp directory is one of the few directories that are world writable by default, according to the Filesystem Hierarchy Standard (FHS)1. The other directories that are usually world writable are /var/tmp and /var/lock, which are also used for temporary or lock files. However, these directories are not as frequently used or as large as /tmp, so they are less likely to fill up the / partition. The /tmp directory also has the sticky bit set, which means that only the owner of a file or directory can delete or rename it2. This prevents users from deleting or modifying other users’ files in /tmp. However, this does not prevent users from creating new files or directories in /tmp, which can still consume disk space and resources. Therefore, it is advisable to have /tmp on a separate partition if possible. References:

• Filesystem Hierarchy Standard
• Sticky bit - Wikipedia

The top-level system directory that is used for files and data that change regularly while the system is running and are to be kept between reboots is /var. The /var directory contains variable data that changes in size as the system runs. For instance, log files, mail directories, databases, and printing spools are stored in /var. These files and data are not temporary and need to be preserved across system reboots. The /var directory is one of the few directories that are recommended to be on a separate partition, according to the Filesystem Hierarchy Standard (FHS)1. This is because the /var directory can grow unpredictably and fill up the / partition, which can cause system instability or failure. By having /var on a separate partition, we can limit the amount of disk space that can be used by variable data and prevent users from affecting the / partition. The /var directory is also a common target for malicious attacks, so having it on a separate partition can improve the security and isolation of the system. References:

• Filesystem Hierarchy Standard

The swapoff command is used to disable swapping on a device or a file. It takes the path of the device or file as an argument, or -a to disable all swaps. Disabling swap can improve the performance of the system if there is enough physical memory, or it can be necessary if the swap size needs to be changed. However, disabling swap can also cause problems if the system runs out of memory and has no swap space to use. References:

• How to Disable Swap in Linux - Linux Handbook
• How to Permanently Disable Swap in Linux? - GeeksforGeeks
• LPI Linux Essentials - 1.1 Operating System Basics

 The command apt-cache can be used to perform a full text search on all available packages on a Debian system. It searches the package names and the descriptions for an occurrence of the regular expression given as a keyword and prints out the package name and the short description1. The syntax is: apt-cache search keyword. For example, apt-cache search openssh will return a list of packages related to OpenSSH2. The other commands are not suitable for this task because:

• apt is a high-level command-line tool that provides a user-friendly way to manage packages, but it does not have a search option3.
• apt-get is a low-level command-line tool that handles the installation and removal of packages, but it does not have a search option4.
• apt-search is not a valid command.
• dpkg is a tool to install, build, remove and manage Debian packages, but it does not have a search option5. It can only list the installed packages with the option -l4. References:
• How To Search For Available Packages From Command Line In Debian, Ubuntu Or Linux Mint [APT] - Linux Uprising Blog
• apt(8) — apt — Debian buster — Debian Manpages
• How to List Installed Packages on Debian | Linuxize
• Debian / Ubuntu Linux search package names with apt-cache command
• dpkg(1) — dpkg — Debian buster — Debian Manpages

 The environment variable LD_LIBRARY_PATH is used to tell the dynamic linker to look in a specific directory for some of a program’s shared libraries. It is a colon-separated list of directories that are searched by the dynamic linker when looking for a shared library to load1. The directories are searched in the order they are mentioned in. For example, if we have a program that depends on a shared library libfoo.so that is located in /home/user/build/lib, we can run the program with:

LD_LIBRARY_PATH=/home/user/build/lib ./program

This will instruct the dynamic linker to search for libfoo.so in /home/user/build/lib before the default directories. The environment variable LD_LIBRARY_PATH can also be appended to an existing value with the += operator, for example:

LD_LIBRARY_PATH+=:/home/user/build/lib

This will add /home/user/build/lib to the end of the LD_LIBRARY_PATH list. The other options are not valid environment variables for the dynamic linker. LD_LOAD_PATH, LD_LIB_PATH, and LD_SHARE_PATH are not recognized by the dynamic linker. LD_RUN_PATH is a linker option that can be used to embed a librarysearch path in the executable at link time, but it is not an environment variable that can be set or modified at run time2. References:

• LPI Exam 101 Detailed Objectives, section 1.101.3
• ld-linux(8) — Linux manual page
• Setting the dynamic linker with an environment variable - narkive