Transfers data from internal storage to user-specified external
  logical units (such as disks, printers, terminals, and pipes) or
  internal files.

  The meanings of the symbolic abbreviations used to represent the
  parameters in the WRITE statement syntax are as follows:

     extu    Is the logical unit or internal file optionally
     or      prefaced by UNIT=.  UNIT= is required if unit is
     intu    not the first element in the clist.

     fmt     Specifies whether formatting is to be used for data
             editing, and if it is, the format specification or an
             asterisk (*) to indicate list-directed formatting.
             The "fmt" is optionally prefaced by FMT=, if "fmt"
             is the second parameter in the clist and the first
             parameter is a logical or internal unit specifier
             without the optional keyword UNIT=.

     nml     Is the namelist group specification for namelist I/O.
             Optionally prefaced by NML=.  NML= is required if
             namelist is not the second I/O specifier.

     rec     Is the cell number of a record to be accessed directly.
             Optionally prefaced by REC= or by an apostrophe (').

     iostat  Is the name of a variable to contain the completion
             status of the I/O operation. Prefaced by IOSTAT=.

     err     Is the label of a statement to which control is
             transferred in the event of an error. Prefaced by
             ERR=.

     end     Is the label of a statement to which control is
             transferred in the event of an end of file. Prefaced
             by END=.

     adv     Specifies advancing (ADVANCE='YES') or nonadvancing
             input (ADVANCE='NO').  The default is 'YES'.

     iolist  Are the names of the variables, arrays, array elements,
             or character substrings from which or to which data
             will be transferred.  Optionally an implied-DO list.

  The control-list parameters are "extu" (or "intu"), "fmt", "nml",
  "rec", "iostat", "err", "end", and "adv".  The I/O list parameter
  is "iolist".