Descritpiton of Commands Widely Used in Pattern Matching /Regular Expressions/PERL Scripting

**************Pattern  Matching********************

*  =>  Including allCharacters including "Nothing". Matches any no of Characters.
?  =>  Including all Characters exactly one Match not includes  "Nothing".

a*b  =>  Matches all files which will Start with Letter  a  and End with b.
*a    => Matches  all Files which will end with letter a.
a*  => Matches  all Files  which will start with the Letter  a.
a?b  => Matches  all the file  which will start with a  and end with b including one more character in Middle.
?ab  => Matches  Files  which will start with any single Letter and ends with  "ab".
ab?  => Matches  files which will start with ab and ends with any more character.
[abc]  =>  Exactly Matches one of "a or b or c".
[!abc] or [^abc] => Exactly Matches one Character  not including "a,b or c".
[c-y] => Matches any character  between c  and  y.