Operating Systems Quiz

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Questions and Answers

Which of the following is an example of an Operating System?

Google Chrome

Microsoft Word

Linux (correct)

Adobe Photoshop

The main goal of an Operating System is to provide a convenient working environment for programmers only.

False

What is the purpose of the 'umask' setting in a shell configuration?

It controls the default access permissions for new files.

_________ is a command to clear the terminal screen.

cls Signup and view all the answers

Match the common Operating Systems with their characteristics:

Windows 11 = Graphical User Interface Linux = Open-source software macOS 14 = Developed by Apple Android = Primarily for mobile devices Signup and view all the answers

Which command is used to create a new directory?

mkdir Signup and view all the answers

The relative path of a file starts with a forward slash (/).

False Signup and view all the answers

What notation is used to represent the home directory in file paths?

~ Signup and view all the answers

To remove a directory, the command used is ______.

rmdir Signup and view all the answers

Which of the following is an example of an absolute path?

/home/user/file.txt Signup and view all the answers

Match the following commands with their functions:

ls = List directory contents cat = Concatenate files and output od = Octal dump of files mkdir = Make a new directory Signup and view all the answers

Hidden files in Linux begin with a period (.) in their filename.

True Signup and view all the answers

What is the command to display the contents of a file on standard output?

cat Signup and view all the answers

Which of the following components is considered the core of the Linux operating system?

Kernel Signup and view all the answers

Linux is not a multi-user operating system.

False Signup and view all the answers

What command would you use to create a directory named 'projects' in Linux?

mkdir projects Signup and view all the answers

The __________ is the command interpreter that provides the user interface in Linux.

Shell Signup and view all the answers

Match the Linux commands with their functions:

date = Print date and time whoami = Display user id logout = Log out pwd = Print working directory Signup and view all the answers

Which distribution of Linux is known for being a free open-source operating system?

Ubuntu Signup and view all the answers

Linux file paths are case insensitive.

False Signup and view all the answers

What protocol was significant in the development of UNIX at Berkeley?

TCP/IP Signup and view all the answers

What does `${#color[@]}` return when the color list has five components?

5 Signup and view all the answers

In Bash, the first command line argument is accessed using $2.

False Signup and view all the answers

What is the index of the first component in a Bash array?

0 Signup and view all the answers

In a Bash script, the command to check a condition using if structure starts with 'if test-______'.

expr Signup and view all the answers

Match the following positional parameters with their corresponding command line arguments:

$0 = ./addsize $1 = file1 $2 = file2 $3 = file3 $# = 3 Signup and view all the answers

What command is used to display the top 20 lines of a file?

head -20 file1 Signup and view all the answers

The command 'mv file1 file2' can be used to move and rename a file at the same time.

True Signup and view all the answers

What command should you use to remove a directory that is not empty?

rm -r dir1 Signup and view all the answers

To check the calendar for the year 2001, use the command '____ 2001'.

cal Signup and view all the answers

Match the commands with their functions:

ls -l = List in long format all non-hidden entries cp = Copy a file rm = Remove files cd = Change directory Signup and view all the answers

Which command will you use to list all entries in a directory, including hidden files?

ls -a dir1 Signup and view all the answers

The 'rm file1 file2' command can delete two files at once.

True Signup and view all the answers

What command would you use to view the current working directory?

pwd Signup and view all the answers

What is the first command you use to give a script file executable permissions?

chmod 700 Signup and view all the answers

In a Bash script, all variables are strictly typed.

False Signup and view all the answers

What does the acronym GCD stand for?

Greatest Common Divisor Signup and view all the answers

The shell implements a programming language that includes variables, expressions, assignment, and __________ structures.

control Signup and view all the answers

Match the following Bash expressions with their meanings:

[[ var ]] = var is defined and is not null [[ -z str ]] = str is zero length [[ arg1 -eq arg2 ]] = arg1 is equal to arg2 [[ -f entry ]] = Is an ordinary file Signup and view all the answers

Which operator is used for logical AND in Bash expressions?

&& Signup and view all the answers

The GCD of two integers can be calculated using the Euclidean algorithm as shown in the sample code.

True Signup and view all the answers

What is the command to display the value of a variable named 'x'?

echo $x Signup and view all the answers

When defining a variable, there should be no spaces around the __________ symbol.

equal to Signup and view all the answers

What will be the output of the command 'echo -n "Enter the 1st positive integer: "'?

Enter the 1st positive integer: Signup and view all the answers

Study Notes

CSC 209 UNIX Tools - Hierarchical Diagram

A hierarchical diagram displays folders and files created in assignment 1
The home directory contains the user account jdoel
The jdoel folder contains multiple subfolders and files
The csc209 folder contains subfolders asgn01 and asgn02
The public_html folder is a subfolder under csc209
The folder csc209 contains the folder esc209
The root directory (/) is the top-level folder

Sign on as a new user using Net-ID (user ID) and password
Verify password and establish user identity and group id
Establish login (home) directory and shell
Announce the presence of email (traditional)
Customize terminal settings
Publish message of the day (motd) (traditional)
Initiate command interpreter (shell)
Perform user-specified initialization (code)
Display prompt and await commands

Password File

The /etc/passwd file historically stores login information
Each line within /etc/passwd represents a user
Each line contains seven pieces of user data separated by colons
Encrypts password in a hash
Modern systems use /etc/shadow or similar mechanisms for security

Shell Initialization Files

The C Shell is the default login shell at Brockport
Initialization files .cshrc and .login are executed on startup of the C shell
In Assignment 1, a .login file is set up to switch to Bash
Bash initialization executes /etc/profile and ~/.bash_profile at login

Sample .bashrc File

The ~/.bashrc file contains important configurations
Sources global definitions from /etc/bashrc (if applicable)
Contains user-specific aliases (e.g., cls, h, lo)
Controls history parameters (e.g., HISTSIZE, HISTFILESIZE)
Sets default access permissions (using umask)
Protects files in redirection
Defines shell prompt (PS1)

What is an Operating System?

OS is a computer's system software in charge of the entire computer system
Provides a convenient working environment and organization of files
Management of computer resources are critical OS functions
Examples of OS include MS-DOS, Windows 11, macOS 14, UNIX, Linux, Android, and iOS

Brief History of UNIX

MULTICS project at MIT influenced early UNIX development
UNIX originated at Bell Labs (AT&T) in 1969 by Ken Thompson and Dennis Ritchie
UNIX System Laboratory (USL)
UNIX extensions and communication protocols (TCP/IP) emerged in the 1980s
Major flavors such as AT&T System 5 Release 4 (SVR4). USL (AT&T) → Novell → Santa Cruz Operations (SCO) BSD 4.4 and some from vendors

UNIX/Linux

Linux is a multi-user, time-sharing, multi-tasking OS
Kernel is the core of the operating system
Shell acts as the user interface and command interpreter
Features include hierarchical file structure and I/O device support.

Simple Linux Commands

date: Displays date and time
who: Lists currently logged-in users
whoami: Displays current user ID
logout: Logs out of the system
pwd: Displays the current working directory
mkdir: Creates a new directory
rmdir: Removes an empty directory
cd: Changes the current working directory
ls: Lists directory contents
chmod: Changes file permissions

Permissions in Linux

The ls -l command provides detailed security information of files and directories
Permissions are specified as three sets of three permissions (read, write, execute)
Permissions are tied to the owner, group, and others

Ordinary File Permissions

Displaying files requires read permissions
Rewriting files requires write permissions
Executing a file requires execute permissions

Directory File Permissions

Moving to directories requires execute permissions
List directories requires read and execute permissions
Creating new directory entries requires write permission
Removing directory entries requires write permissions

Default Access Permissions

Default file permissions are 666 (for files) and 777 (for directories)
umask (user mask) controls what permissions are removed
Using ~/.bashrc to set umask to 077 changes default permissions

Superuser (root)

Superuser (root) is the administrator account
Can access, create, or delete any files or directories irrespective of permissions
Superuser bypasses permission restrictions

Format of Linux Commands

Commands typically follow the format command_name [options] [argument]
Options are single characters preceded by a hyphen
Arguments are often necessary to use the commands effectively

Handling errors while typing commands

ctl-h or Backspace to delete previous character
ctl-w to delete the previous word
ctl-u to delete the entire command

On-line help (man command)

Use man to display help for commands
Example man cat provides documentation for the cat command

Hierarchical File System

Organizes files and directories in a tree-like structure
Root directory (/) is the top-level directory
cd command navigates between directories
pwd displays current working directory

Absolute and Relative Path Names

Absolute paths start with a forward slash (/) or a tilde (~)
Relative paths are relative to the current working directory

File Manipulation Commands

cat: Concatenates files and prints to the standard output
od: Displays content in octal format
more: Displays files one screen at a time

Other File Commands

head: Displays the first part of a file
tail: Displays the last part of a file
cmp: Compares two files; shows the first difference
diff: Compares two files; shows all differences
cal: Displays a calendar

File System Commands

piico, nano, emacs: Editors for file manipulation
cp: Copies files
mv: Moves or renames files
rm: Removes files
rm -i: prompts before deleting files

Directory Listing Commands

ls: Lists files and directories in the current working directory
ls -a: Includes hidden files in listing
ls -l: Displays file information in long format
ls -ld: Lists directory information in long format

Directory Manipulation Commands

mkdir: Creates a new directory
rmdir: Removes an empty directory
rm -r: Recursively removes a directory (be cautious)
cd: Changes the current working directory
pwd: Shows current working directory

Bash Special Characters

Special characters define actions such as input/output redirection, variable substitutions, and more

Shell Substitutions and Quoting

The shell performs input processing of various substitutions
Three methods are available to quote
Use \ (backslash) to quote a character
Use single quotes to disable substitutions entirely
Use double quotes to allow certain substitutions but restrict wildcard expansion

History Substitution

Accessing previously entered commands or parts
Variables like HISTSIZE and HISTFILESIZE influence command history management

Aliases Substitution

Alias commands to shorten the names for frequently used tasks
A list of all aliases can be obtained with the alias command
An alias is undone using unalias

Shell Variable Value Substitution

Accessing the values stored in shell variables using the "$" symbol
Using set displays all current shell variables
Removing particular variables using unset

Command Output Substitution

Performing a command, and using the output as a value
Enclosing the command in backticks

File Name Expansion

Wildcards and file name expansion
Example: ls -l * will generate a listing of all entries in the current directory
Use \ or single quotes to disable wildcards

Special Characters and Quoting

Backslash escapes the effect of special characters inside the quotes
Single and double quotes both prevent certain interpretations

Redirection and Pipe

Redirecting input from a file with input_file < or redirecting output to a file with >output_file
Using a pipe to chain commands (e.g., command1 | command2)

Linux Filenames and Shell Substitutions

Filename length and character restrictions
Standard usage for creating and deleting files
Filename wildcards and usage, e.g., "*and?`

Linux Directories, Inodes, Links

Information of file and directories that describe the Linux file system
Inode number is central to Linux structure to maintain all file attributes
Hard and soft links

Shell Working and Process Control

Shell activities and commands (e.g. ps, jobs, fg)

Process Control Commands

Using ps and kill to manage running processes

Locating Files in File System

Using find command to locate files
Use criteria for location

Selection Criterion

find command criteria to meet when listing files

Regular Expressions

Method of describing a set of text strings using meta characters

Stream Editor (sed)

sed is used for repetitive editing tasks
Editing instructions can be in a separate file or given inline
sed performs edits on each line

Bash Scripts

Shell scripts are programs for the shell
How to execute code in files

Bash Script Basics

User-defined variables, use of $ symbol for accessing variables, arithmetic operations, string handling

Test Expressions

Logical conditions to check whether a variable is true or false

File Queries

Examine file types, permissions, sizes with find command

Multivalued Variables (Arrays)

Array variables and how to access them

Command Line Arguments

Accessing command line arguments passed to a script (e.g., $1, $2, $@ , $#).

Bash Control Structures

Conditional statements and loops for Bash scripts (like if, elif, else, case, while, and for).

Examples of Bash Scripts

Practical demonstrations of using the discussed concepts

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Description

Test your knowledge on Operating Systems with this quiz that covers key concepts, commands, and characteristics of different systems. From shell configurations to directory management, assess your understanding of both Linux and general Operating System principles.

Operating Systems Quiz

Choose a study mode

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Questions and Answers

Which of the following is an example of an Operating System?

The main goal of an Operating System is to provide a convenient working environment for programmers only.

What is the purpose of the 'umask' setting in a shell configuration?

_________ is a command to clear the terminal screen.

Match the common Operating Systems with their characteristics:

Which command is used to create a new directory?

The relative path of a file starts with a forward slash (/).

What notation is used to represent the home directory in file paths?

To remove a directory, the command used is ______.

Which of the following is an example of an absolute path?

Match the following commands with their functions:

Hidden files in Linux begin with a period (.) in their filename.

What is the command to display the contents of a file on standard output?

Which of the following components is considered the core of the Linux operating system?

Linux is not a multi-user operating system.

What command would you use to create a directory named 'projects' in Linux?

The __________ is the command interpreter that provides the user interface in Linux.

Match the Linux commands with their functions:

Which distribution of Linux is known for being a free open-source operating system?

Linux file paths are case insensitive.

What protocol was significant in the development of UNIX at Berkeley?

What does ${#color[@]} return when the color list has five components?

In Bash, the first command line argument is accessed using $2.

What is the index of the first component in a Bash array?

In a Bash script, the command to check a condition using if structure starts with 'if test-______'.

Match the following positional parameters with their corresponding command line arguments:

What command is used to display the top 20 lines of a file?

The command 'mv file1 file2' can be used to move and rename a file at the same time.

What command should you use to remove a directory that is not empty?

To check the calendar for the year 2001, use the command '____ 2001'.

Match the commands with their functions:

Which command will you use to list all entries in a directory, including hidden files?

The 'rm file1 file2' command can delete two files at once.

What command would you use to view the current working directory?

What is the first command you use to give a script file executable permissions?

In a Bash script, all variables are strictly typed.

What does the acronym GCD stand for?

The shell implements a programming language that includes variables, expressions, assignment, and __________ structures.

Match the following Bash expressions with their meanings:

Which operator is used for logical AND in Bash expressions?

The GCD of two integers can be calculated using the Euclidean algorithm as shown in the sample code.

What is the command to display the value of a variable named 'x'?

When defining a variable, there should be no spaces around the __________ symbol.

What will be the output of the command 'echo -n "Enter the 1st positive integer: "'?

Study Notes

CSC 209 UNIX Tools - Hierarchical Diagram

Login and Bash Initialization

Password File

Shell Initialization Files

Sample .bashrc File

What is an Operating System?

Brief History of UNIX

UNIX/Linux

Simple Linux Commands

Permissions in Linux

Ordinary File Permissions

Directory File Permissions

Default Access Permissions

Superuser (root)

Format of Linux Commands

Handling errors while typing commands

On-line help (man command)

Hierarchical File System

Absolute and Relative Path Names

File Manipulation Commands

Other File Commands

File System Commands

Directory Listing Commands

Directory Manipulation Commands

Bash Special Characters

Shell Substitutions and Quoting

History Substitution

Aliases Substitution

Shell Variable Value Substitution

Command Output Substitution

File Name Expansion

What does `${#color[@]}` return when the color list has five components?