Linux terms Flashcards
Bootloader
A piece of code that runs to guide the booting process to start the operating system. Parrot Linux uses the GRUB Bootloader.
OS Kernel
The kernel is the main component of an operating system. It manages the resources for system’s I/O devices at the hardware level.
Daemons
Background services are called “daemons” in Linux. Their purpose is to ensure that key functions such as scheduling, printing, and multimedia are working correctly. These small programs load after we booted or log into the computer.
OS Shell
The operating system shell or the command language interpreter (also known as the command line) is the interface between the OS and the user. This interface allows the user to tell the OS what to do. The most commonly used shells are Bash, Tcsh/Csh, Ksh, Zsh, and Fish.
Graphics server
This provides a graphical sub-system (server) called “X” or “X-server” that allows graphical programs to run locally or remotely on the X-windowing system.
Window Manager
Also known as a graphical user interface (GUI). There are many options, including GNOME, KDE, MATE, Unity, and Cinnamon. A desktop environment usually has several applications, including file and web browsers. These allow the user to access and manage the essential and frequently accessed features and services of an operating system.
Utilities
Applications or utilities are programs that perform particular functions for the user or another program.
Hardware
Peripheral devices such as the system’s RAM, hard drive, CPU, and others.
Kernel
The core of the Linux operating system whose function is to virtualize and control common computer hardware resources like CPU, allocated memory, accessed data, and others. The kernel gives each process its own virtual resources and prevents/mitigates conflicts between different processes.
Shell
A command-line interface (CLI), also known as a shell that a user can enter commands into to execute the kernel’s functions.
System Utility
Makes available to the user all of the operating system’s functionality.
/
The top-level directory is the root filesystem and contains all of the files required to boot the operating system before other filesystems are mounted as well as the files required to boot the other filesystems. After boot, all of the other filesystems are mounted at standard mount points as subdirectories of the root.
/bin
Contains essential command binaries.
/boot
Consists of the static bootloader, kernel executable, and files required to boot the Linux OS.
/dev
Contains device files to facilitate access to every hardware device attached to the system.
/etc
Local system configuration files. Configuration files for installed applications may be saved here as well.
/home
Each user on the system has a subdirectory here for storage.
/lib
Shared library files that are required for system boot.
/media
External removable media devices such as USB drives are mounted here.
/mnt
Temporary mount point for regular filesystems.
/opt
Optional files such as third-party tools can be saved here.
/root
The home directory for the root user.
/sbin
This directory contains executables used for system administration (binary system files).
/tmp
The operating system and many programs use this directory to store temporary files. This directory is generally cleared upon system boot and may be deleted at other times without any warning.
/usr
Contains executables, libraries, man files, etc.
/var
This directory contains variable data files such as log files, email in-boxes, web application related files, cron files, and more.
\d
Date (Mon Feb 6)
\D{%Y-%m-%d}
Date (YYYY-MM-DD)
\H
Full hostname
\j
Number of jobs managed by the shell
\n
Newline
\r
Carriage return
\s
Name of the shell
\t
Current time 24-hour (HH:MM:SS)
\T
Current time 12-hour (HH:MM:SS)
\@
Current time
\u
Current username
\w
Full path of the current working directory
whoami
Displays current username.
id
Returns users identity
hostname
Sets or prints the name of current host system.
uname
Prints basic information about the operating system name and system hardware.
pwd
Returns working directory name.
ifconfig
The ifconfig utility is used to assign or to view an address to a network interface and/or configure network interface parameters.
ip
Ip is a utility to show or manipulate routing, network devices, interfaces and tunnels
netstat
Shows network status.
ss
Another utility to investigate sockets.
ps
Shows process status.
who
Displays who is logged in.
env
Prints environment or sets and executes command.
lsblk
Lists block devices.
lsusb
Lists USB devices
lsof
Lists opened files.
lspci
Lists PCI devices.
-a, –all
print all information, in the following order, except omit -p and -i if unknown:
-s, –kernel-name
print the kernel name
-n, –nodename
print the network node hostname
-r, –kernel-release
print the kernel release
-v, –kernel-version
print the kernel version
-m, –machine
print the machine hardware name
-p, –processor
print the processor type (non-portable)
-i, –hardware-platform
print the hardware platform (non-portable)
