All the Operating system based on the concept of GUI (Graphical User Interface).

Red Hat and SUSE Enterprise.

(i) Red Hat
(ii) Ubuntu
(iii) Cent OS
(iv) Linux Mint

By choosing an option logout through the session indicator on the far right side of the top panel.

The server distribution in Linux OS:
(i) Ubuntu Linux
(ii) Linux Mint
(iii) Arch Linux
(iv) Deepin
(v) Fedora
(vi) Debian
(vii) Centos

(i) The window is an area on the screen that displays information for a specific program.
(ii) Window is a typical rectangular area in an application or a document or a-dialog.
(iii) A typical window includes a title bar along the top that describes the contents of the window, A followed by a toolbar that contains user interface buttons.
(iv) Most of the window's remaining area is used to display the content.

Difference between Thunderbird and Firefox in Ubuntu:
(i) Thunderbird is inbuilt email software of ubuntu whereas Firefox is a web browser.
(ii) Thunderbird is used to access email such as Gmail, hotmail whereas Firefox is used to open web pages including e-mail.

(i) Ubuntu has less hardware support for commercial/industrial/medical/ logistical therefore its less voted for use in big time backends.
(ii) Ubuntu doesn't support middlewares such as C panel, cloud linux and a plethora of other infrastructure or monitoring tools.
(iii) Hard to install graphic drivers especially for old hardwares. It is not possible to play the modern games, because of poor graphics quality.
(iv) The user switching from windows will not like the user experience on Ubuntu and will have difficulty in operating the OS.
(v) Ubuntu is not capable of playing MP3 files by default.

(i) The Title Bar and control buttons - The title bar will display the name of the program and the name of the document that has been currently opened and also contains control buttons like Minimize, MaximizelRestore and Close buttons.
(ii) The Menu bar - The menu bar is seen under the title bar. Menus in the menu bar can be accessed through shortcuts involving the Alt key and the mnemonic letter that appears underlined in the menu title. Additionally, pressing Alt or F 10 brings the focus on the first menu of the menu bar.

(iii) In Windows 7, in the absence of the menu bar, you have to click organize and in the sub menu list, click the layout option from it and then select the desired item from that list.
(iv) The Workspace: The Workspace is the area in the document window where you enter or type the text of document. It is the point of insertion for typing within the document.
(v) The Scroll bars: A scrollbar is an interaction technique in which continuous text, pictures, or any other content can be scrolled in a predetermined direction (up, down, left, or right) on a computer display so that all contents can be viewed, even if only a fraction of the content can be seen on a device's screen at a time. Refer figure 5.10 to view the Scroll bars.
(vi) Corners and borders: The corners and borders of the windows help to drag and hence help to resize the Windows. The mouse cursor changes to a double arrow when positioned over a border or a corner. Drag the border or corner in the direction indicated by the double arrow to the desired shape.
(a) The corners can be resized diagonally by dragging it across any of the corners. It will resize the window on all the sides simultaneously.
(b) On the other hand, the borders will let you to resize the window by either dragging it in left side, right side, from the top or from the bottom of the window.
(c) It will change the size of the window at one side only depending on the side in which the dragging is made.

Application Icons:
(i) These icons are representing Software package's logo. Double-click over this icon, the related application gets invoked.
(ii) Shortcut Icons: These icons point to a particular application or file or folder. By double clicking over them the related application or file or folder will open. This represents the shortcut form to open a particular application.
(iii) Document Icons: Active document window which is a window within an application window is called as the document icon.

In Ubuntu OS:
(i) Create a file: By right clicking in the desktop and also files be created by using file menu.
(ii) Delete a file: By using right-click choosing a move to trash or by using the menu.
(iii) Rename a file: By using right-click and choosing rename option.
(iv) Save a file: Press ctrl + x or F2 to exit. You will. then be asked if you want to save. (or) Press ctrl+ 0 or F3 and ctrl + x or F2 for save and exit.
In Windows OS:
(i) Create file: Open an application and create by using file menu.
(ii) Delete a file: By right click on a file and choosing the delete option to delete a file.
(iii) Rename a file: By right click on a file and choosing rename option to rename a file.
(iv) Save file: Press ctrl+S or file - save to save the file.