ALT OS

 Disable all desktop notification with ‘Do Not Disturb’ button

Getting distracted by desktop notifications? You can utilize the ‘do not disturb’ option to toggle the desktop notifications.​

Fractional scaling

Ubuntu finally brings fractional scaling. If you always found that icons at 100% looked too small and bit too big at 200%, you can take advantage of the fractional scaling.

Linux Kernel 5.4

Ubuntu 20.04 features the latest LTS kernel 5.4. This means that you get native ExFAT support and all the other performance improvements and new hardware supports that come with it.​

Improved ZFS support

* Ubuntu became the first mainstream Linux distribution to introduce ZFS as root with Ubuntu 19.10 release.​
* While Linus Torvalds may not like ZFS, it is still a popular file system. Ubuntu 20.04 sees improved support for ZFS.​​

**WireGuard VPN specially backported**​

* Though Ubuntu 20.04 won’t be using kernel 5.6 at least immediately, it is backporting WireGuard in kernel 5.4.​
* WireGuard is the new buzz in VPN industry and thus including WireGuard in its kernel should give some boost to Ubuntu 20.04 in the cloud scenario.​

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 No 32-bit systems for Ubuntu 20.04

Ubuntu is not providing ISO for 32-bit computers for a few years now. But at least existing 32-bit Ubuntu users could still upgrade to Ubuntu 18.04.​

That’s not the case anymore. You cannot upgrade to Ubuntu 20.04 if you are using 32-bit Ubuntu 18.04. If you try to run the upgrade, you’ll see an error of this kind.​

Under the hood improvements

* GNOME 3.36 is less resource hungry and it feels sleek and light to use​
* There are improvements to Thunderbolt support​
* Most of the software have been upgraded to newer version​
* You’ll get NVIDIA drivers on the ISO itself​

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**Operating System**

A special computer program that controls the computer hardware.

Operating System

Serves as a liaison between the consumers and the resources.

Resource Allocator

the OS manages computer resources such as CPU time, memory, file storage, I/O devices, etc.

Control Program

 it controls the execution of programs and I/O devices.

UNIX Services

Program Execution , I/O Operations , File System Handling, Error Detection

*Program Execution*

*loads the user program in memory and runs it.*

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I/O Operations

*responsible for reading & writing data from I/O devices.*

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**File System Handling**

*handles file organization, creation, and deletion.*

**Error Detection**

Address errors within the computer system

**UNIX Varieties & Benefits**

* Based on an open standard


* Supported on wide variety of computers
* Multi-tasking; multi-user
* Hierarchical File System
* TCP/IP tightly integrated
* True 64-bit architecture

File System

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Tree-structured group of directories.

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Subdirectory

Directory below another directory

Common Subdirectories

/usr directory, /optional directory, /devices directory, /etc directory, /export/home directory, /kernel directory ,*/var* *directory*

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**OS Components**

Kernel ,Shell ,File System

Files

Contained in directories & subdirectories

Directory

File locations and subdirectories

Shells

Bourne shell ($) , Korn shell ($) , *C shell (%)*

,*POSIX shell* 

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/usr directory

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exe.files, system admin utils, library routines

/optional directory

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 apps & third-party apps

/devices directory

pointer files to device names

/etc directory

sysadmin files

/export/home directory

user home directories

/kernel directory

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basic OS files

*/var* *directory*

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print spooling & mail system error messages

Kernel

 *manages computer operation*

Shell

*renders the computer user interface*

File System

organizes computer info

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*Bourne shell ($)*

Original shell program

Bourne shell ($)

Provides a UNIX system command interpreter

Korn shell ($)

An enhanced Bourne shell

Korn shell ($)

Added features such as aliasing and history

Korn shell ($)

Widely-used & industry standard

C shell (%)

California Shell

C shell (%)

Based on the C language

C shell (%)

Allows recalling and editing of commands and aliasing

*POSIX shell*

Similar to Korn shell

*POSIX shell*

Command programming language and interpreter

*POSIX shell*

Supports command history, line editing, file name completion, aliasing, and job control

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**$ whatis “command”**

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Tells you what the command does.

**$ rm -d "directory"**

 delete directory

$ ls

view directories

$ man

see list of parameters of command

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**$ mkdir "directory"**

create a directory

$ date

Display the date and time

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**$ passwd**

Assign a login password

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**$ sudo apt install “package”**

Install a package.

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**$ sudo apt install sysvbanner**

Install system banner.

**$ banner** **‘text here’**

Display text in a banner.

$ who , $ finger

Determine currently logged-in user.

$ whoami

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Determines who is logged-in at a specific terminal.

Login ID

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Unique , Limited to 8 lower case letters and numbers

Passwords

* No less than 6 and no more than 8 characters


* Case sensitive
* 3 characters different from login ID

Regular User

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* Created by sysadmin
* Can run apps and customize working environment
* Can create or modify files

Changing Passwords

* $passwd


* Done at command line
* Enter current pass
* Enter new pass
* Re-enter new pass

Command-Line Syntax

* Case-sensitive


* Can type 2 commands on a single line separated by “;”.

 More default theme variants and the aubergine touch​

Canonical is experimenting with themes again. In Ubuntu 19.10, the default Yaru theme introduced a dark version. Ubuntu 20.04 takes it further three variants of the default Yaru theme: Light, Dark and Standard

GNOME 3.36 and all the visual and performance improvements that come with it​

Ubuntu 20.04 has the latest GNOME 3.36 release. This means that all the new features in 3.36 are also available for Ubuntu 20.04.