              if list
              then list
              [ elif list ; then list ] ...
              [ else list ]
              fi     The if list is executed, and, if it  returns
                     a  zero  exit  status, the then list is exe-
                     cuted.  Otherwise, the elif list is executed
                     and,  if its value is zero, the then list is
                     executed.   If  each   elif   list   returns
                     nonzero, the else list is executed.

              if ( list ) sublist
                     A short form of if.

              if ( list ) {
              list
              } elif ( list ) {
              list
              } ... else {
              list
              }      An  alternate  form  of  if. The parentheses
                     surrounding list can be omitted if the  only
                     command in the list is a conditional expres-
                     sion of the form [[ exp ]] (see below).
