unix

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Unix systems are characterized by a modular design that is sometimes called the, what?

Unix philosophy

The Unix operating system should provide a set of simple tools known as, what?

coreutils or core utilities

What is the name of the GNU Kernel?

Hurd or Linux for GNU/Linux

The POSIX shell is the same as which shell?

Bourne Shell

What is the default shell on GNU/Linux?

BASH (Bourne Again SHell)

True or False: The CLI, terminal, and shell are just different names for the same thing.

False

What is the root of the filesystem?

/

What is the name of the user that lives in kernel land?

Root user

What is the home directory of the root user?

/root

What is the administrator on a Linux system?

A user that is allowed to run commands as root

What is a device driver?

Lets the OS know how to access and use information from that device

What are two types of device drivers?

Kernel-Mode and User-Mode

Where are log files kept?

/var/log

Where are system configuration files located?

/etc

True or False: The /usr/bin directory contains required binaries.

False

What is the ~ short for?

Home directory

What is a single dot short for?

The current working directory

Where does the absolute path for a file or directory start?

/

What is the fundamental interface between an application and the Linux kernel?

System calls

What is the command to pull up system calls by number on a Linux machine?

ausyscall --dump

What is the name of the C library on GNU/Linux called?

glibc (GNU C library)

What is the file type for executable files in Unix/Linux?

elf

What is the GNU C library called?

glibc

What does the mmap system call do?

Maps a file to memory

True or False: A reboot is required when one installs a LKM?

False

What is the command to list loaded kernel modules?

lsmod

What does the .ko file extension stand for?

Kernel Object

What are some of the common arguments used with the ps command?

-ef, -elf, aux

What is a type of process that runs in the background without any human interaction?

Daemon

What are the three types of login shells?

BASH, GUI, SSH

What shell actively reads commands from user input?

Interactive Shell

What argument is used with the "su" command to open a BASH login?

-l or --login

What argument opens a BASH login with the "bash" command?

- or -l or --login

What is the restricted BASH shell called?

rBASH

What command is used to print environmental variables?

printenv or env

What environmental variable is checked when we execute a command in the shell?

PATH

SSH's most notable applications are what?

Remote login and command line execution

Name one file transfer protocol based on SSH.

SFTP (SSH File Transfer Protocol)

What is an administrator account?

A user that is allowed to run commands as root with the sudo command

What type of account do users like Apache have?

Service account

What of accounts belong to users like sys or a daemon?

System account

What file contains user information?

/etc/passwd

Where are user password hashes stored?

/etc/shadow

Where are local user configurations stored?

~/.bashrc

What restricts the rights and access of a user to the minimal amount required to perform their role?

Principle of Least Privilege

What element of user management says administrators of a system should not share accounts?

Individual accounts

What are some of the basics of password management?

Passwords should be changed periodically, do not reuse passwords, required complexity

What command is used to check network connectivity?

ping

What command is used to display the routing table?

route

What information do you need to configure an IP address?

The IP address, subnet mask, and default gateway.

What are three command line tools used to interact with Networkd?

networkctl, nmtui, and nmcli

The d after a process name ie Networkd stands for what?

Daemon

Samba’s functionality comes from what two protocols?

SMB and CIFS

What does Samba do?

Provides file and print sharing between different operating systems.

Samba security modes are set in which file?

smb.conf

What are the two security modes in Samba?

share-level and user-level

What protocol does LDAP sit on top of?

TCP/IP

What are two common implementations of LDAP?

Active Directory for Windows and OpenLDAP for Linux

The majority of Apache servers run on what system?

Linux

Where is the index.html file located? (for Apache)

/var/www/html

What are the symbols used to denote request and response headers?

> for request and < for response

What code means everything worked correctly?

200 OK

Why study SQL in this section?

Backbone of Apache, SQL Injection Vulnerabilities

Why study JavaScript in this section?

Frontend of Apache, JavaScript Injection Vulnerabilities

SystemV has run levels, what did SystemD migrate too?

Targets

In SystemV Linux what is the centralized configuration file?

/etc/inittab

What is rsyslog?

Rocket Fast Syslog Server

What command is used for querying systemd for logs, and has taken a good part of the old syslog?

journalctl

What command is used to edit the crontab?

crontab -e

What is each field of the crontab?

Minute, hour, day of month, month of year, day of week, command/script to execute

What is the Debian package manager called?

APT (Advanced Package Tool)

A package is a container for ?

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