Various special characters

Hi to all my dear friends and visitors of this blog. ‘*’is used for representing any number of characters when used in the prefix or in the suffix for example, let us assume that we have a group of files beginning with ‘cha’.
If we want to list these files 
Ending with “ing” can be performed on them.’?’Character is used to represent one character only either in the prefix or in the suffix of the filename. There is exactly one character after ‘cha’ for ‘cham.c’ and ’chan.c’ .hence these two files are displayed.”[]”is used to access a related files. A shell has different types of variables namely user defined and environment variables. The environment variables are used to define our environment.