Linux Essentials LPI 010-160 Lecture Review

A collection of vocabulary flashcards based on Linux Essentials LPI 010-160 lecture notes covering basic commands, file systems, permissions, and system administration.

Hard Disk Drives (HDD) vs. Solid State Disks (SSD)

Hard disks possess a motor and moving parts, whereas solid state disks do not and provide faster access to stored data.

top

A command that displays running processes, typically ordered by CPU or RAM consumption.

Reverse DNS Name Storage

For the IP address $198.51.100.165$, the name is stored in the PTR record for $165.100.51.198.in-addr.arpa$.

host

A command used to resolve a DNS name to an IP address.

free

A command that displays information regarding total, used, free, shared, buff/cache, and available memory.

dmesg

A command used to display the contents of the Linux kernel's ring buffer; it may overwrite older information with newer data.

last

A command that displays login information, such as the user, tty, and timestamp of recent sessions.

UID of root

The numerical user ID assigned to the root user is $0$.

SATA bus

A type of bus used to connect hard disk drives with the motherboard.

CentOS

A Linux distribution derived from Red Hat Enterprise Linux that allows for the application of Red Hat knowledge without a subscription.

chmod 654 file.txt

A command that sets a regular file's permissions to $-rw-r-xr--$.

File Ownership

Every file in Linux is owned by exactly one user and one group.

/tmp/ Permissions

The standard permissions set on the /tmp/ directory are $rwxrwxrwt$.

useradd -m tux

A command that adds the new user tux and creates a home directory for them with default configuration files.

/etc/passwd

A file that stores information including the username, the numerical user ID, and the encrypted password.

tar -z and tar -j

Two tar options used specifically to handle compression.

for

The keyword used in a shell script to initiate a loop.

tar -cf work.tar ./work/

A command that creates an archive file named work.tar from the contents of the ./work/ directory.

less Exit Key

The key pressed to exit the less command is $q$.

Script Execution Methods

Valid shell scripts can be executed using either $./test.sh$ (if the execute bit is set) or $bash test.sh$.

find /home -name foo.txt

A command that searches for the file foo.txt within the /home directory.

Linux Distribution

A bundling of the Linux kernel, system utilities, and other software.

RPM

The package management tool utilized in Red Hat-based Linux systems.

Inkscape

A graphical editor used for vector graphics.

Raspberry Pi OS Storage

The operating system is stored on a removable SD card inserted into the device.

Free Software License

Defines the conditions for modifying and distributing the licensed software.

Web Browser Cookies

Small files used to support the identification and tracking of users, which can be considered a security or privacy risk.

Cloud Computing Service Categories

Typical services offered by public cloud providers include Platform as a Service (PaaS), Infrastructure as a Service (IaaS), and Software as a Service (SaaS).

Root Privilege Indicator

The # character in a shell prompt indicates the shell is running with root privileges.

man and info

Two commands used to access documentation and information on the proper use of other commands like ls.

Recursive Directory Listing

A listing that includes the content of a directory and all of its sub-directories.

rmdir

A command used to remove a directory, provided that the directory is empty.

/usr/share/doc/

A directory containing documentation, information, and example configuration files for installed software packages.

PATH Environment Variable

A variable that allows the execution of commands without needing to know the specific location of the executable.

DNS Record Types for IP addresses

Record types that hold IP addresses include A and MX (mail exchange) records.

DHCP

A protocol used for the automatic configuration of IP addresses.

/dev/sda2

The device file representing a specific hard disk partition.

Linux Hardware Drivers

Software components either compiled directly into the Linux kernel or loaded as kernel modules.

/proc/

A directory that contains one subdirectory for every currently running process.

Ubuntu Linux LTS and Red Hat Enterprise Linux

Linux distributions suitable for servers intended to host services for several years with security updates.

/var

A directory that must be mounted with read and write access if it is located on its own dedicated file system.

chown

The command used to change the ownership of a file.

/etc/skel

A directory containing default configuration files that are copied to a new user's home directory upon account creation.

Symbolic Link

A type of link that has the ability to point to a file residing on another file system.

/etc/group

A source file containing information about group IDs and memberships.

passwd Tasks

The passwd command can be used to lock a user account or (according to the transcript) create a new user account.

su

A command that runs a shell or another command as a different user.

ls -R

The specific ls parameter used to print a recursive listing of directory contents.

pwd

The command that outputs the absolute path to the current working directory.

? (Regular Expression)

A regular expression operator that matches the preceding character zero or one time.

export

A command used to set an environment variable, such as USERNAME=bob, making it available to child processes.

Shell Script Return Value

The numeric value returned by a shell script after a successful execution is $0$.

grep -i

A command option used to find lines in a file that match a term regardless of case sensitivity.

Apache HTTPD and NGINX

Two common examples of programs used as web servers.

Private Web Browser Window

A window that does not persistently store cookies, keep records in browser history, or send regular stored cookies.

Package Repository

The preferred source for installing new applications in a Linux-based operating system.