sed command with Regular Expression in Unix or Linux..

In this tutorial,I have talked about regular expression in Unix or Unix with sed command same as grep command

Please see the below cheat sheet for reference.

*asterisk----0 or many
.period------exact one occurance
-range-------a-z,A-Z,Aa-Zz,0-9
[]square bracket--matches one char enclosed eg[a-z]..matches any one character
/backslash--------------escape the reserved meaning of special character*,/$
^carot-------start
$end---------end