~~                           Match Operator

 exp ~~ re     Test if re matches a string in exp
 exp           Any expression
 re            Any expression

    Expressions  'exp'  and  're'  are  evaluated,  'exp' is converted to a
    string  (if  it  is  not  already)  and  're' is converted to a regular
    expression (if  it is  not already)  and the  string value  of 'exp' is
    scanned for the regular expression 're'.   A value of TRUE is  returned
    if a matching string is found, otherwise a value of FALSE is returned.

!~                           Not Match Operator

 exp !~ re     Test if re does not match a string in exp
 exp           Any expression
 re            Any expression

    Expressions  'exp'  and  're'  are  evaluated,  'exp' is converted to a
    string  (if  it  is  not  already)  and  're' is converted to a regular
    expression (if  it is  not already)  and the  string value  of 'exp' is
    scanned for the regular expression 're'.   A value of TRUE is  returned
    if NO matching string is found, otherwise a value of FALSE is returned.