Choose an option logout through the session indicator on the far right side of the top paner.

Open Source refers to a program or software in which the source code is available in the web to the general public free of cost.

Save - This will save the document without asking for a new name or location. It will overwrite the original.
Save As - This will prompt you to save the document using a dialog box. This allows to change the file name or location.

(i) Due to low capacity of main memory (RAM) the system many hang while working with multiple files.
(ii) To reduce it increase the size of main memory and other reasons for hanging is over heating, driver corruption or errors, software errors and computer virus.

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 move to trash or by using 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+ O or F3 and ctrl + x or F2 for save and exit.
In windows OS:
(i) Create file: Open an application and created by using file menu.
(ii) Delete a file: By right click on a file and choose delete option to delete a file.
(iii) Rename a file: By right click on a file and choose rename option to rename a file.
(iv) Save file: Press ctrl+S or file-save to save the file.