Performing character substitution on a string

If regexp is a Find function, then regsub is equivalent to Find and Replace. The regsub command accepts a string and using Regular Expression pattern matching, it locates and, if desired, replaces the pattern with the desired value. The syntax of regsub is similar to regexp as are the switches. However, additional control over the substitution is added. The switches are as listed next:

Switch	Description
-all	Causes the command to perform substitution for each match found The & and \n sequences are handled for each substitution
-expanded	Allows use of expanded regular expression wherein whitespace and comments are ignored
-line	Enables newline-sensitive matching similar to passing the linestop and lineanchor switches
-linestop	Changes the behavior of [^] bracket expressions so that they stop at newline characters
-lineanchor	Changes the behavior of ^ and $ (anchors) so that they match both the beginning and end of...