          regexp ?-indices? ?-nocase? exp string ?matchVar? ?subMatchVar...?
               Determines whether the regular expression  exp  matches
               part or all of string and returns 1 if it does, 0 if it
               doesn't.  See REGULAR EXPRESSIONS  above  for  complete
               information  on the syntax of exp and how it is matched
               against string.
               If the -nocase  switch  is  specified  then  upper-case
               characters  in  string are treated as lower case during
               the matching  process.   The  -nocase  switch  must  be
               specified before exp and may not be abbreviated.

               If additional arguments are specified after string then
               they  are  treated  as the names of variables to use to
               return  information  about  which  part(s)  of   string
               matched  exp.   MatchVar  will  be  set to the range of
               string that matched all of exp.  The first  subMatchVar
               will  contain the characters in string that matched the
               leftmost parenthesized subexpression  within  exp,  the
               next  subMatchVar  will  contain  the  characters  that
               matched the next  parenthesized  subexpression  to  the
               right in exp, and so on.

               Normally, matchVar and the subMatchVars are set to hold
               the  matching  characters from string.  However, if the
               -indices switch is specified then  each  variable  will
               contain  a  list  of  two  decimal  strings  giving the
               indices in string of the first and last  characters  in
               the  matching range of characters.  The -indices switch
               must be specified before the exp argument and  may  not
               be abbreviated.

               If there are more more subMatchVar's than parenthesized
               subexpressions   within   exp,   or   if  a  particular
               subexpression in exp doesn't  match  the  string  (e.g.
               because  it  was  in  a  portion of the expression that
               wasn't matched),  then  the  corresponding  subMatchVar
               will be set to ``-1 -1'' if -indices has been specified
               or to an empty string otherwise.
