Compares the contents of two disk files and  creates  a  listing  of
  those records that do not match.

  Format:


    DIFFERENCES  master-file-spec [revision-file-spec]

Additional information available:

ParametersCommand QualifiersExamples

 master-file-spec

  Specifies the name of the primary input file to be compared.

  The file specification must include a file name and a file type.  No
  wildcard characters are allowed in the file specification.

 revision-file-spec

  Specifies the name of the secondary input file to be compared.   Any
  nonspecified  fields  default  to  the  corresponding  fields of the
  primary input file specification.

  If you do not  specify  a  secondary  input  file,  the  DIFFERENCES
  command uses the next lower version of the primary input file.

  No wildcard characters are allowed in the file specification.

Additional information available:

/CHANGE_BAR/COMMENT_DELIMITER/IGNORE/MATCH
/MAXIMUM_DIFFERENCES/MERGED/MODE/NUMBER/OUTPUT
/PARALLEL/SEPARATED/SLP/WIDTH/WINDOW

 /CHANGE_BAR[=(format[,...])]

 Requests that the output contain a listing of  the  associated  files
  with  a  change  bar  character next to the lines that do not match.
  You can specify any of the following format keywords:

  c             A change bar character.

  NUMBER        Include line numbers.

  NONUMBER      Do not include line numbers.

  In ASCII output mode, the change bar character parameter specifies a
  one-character  code  that  will  appear  in  the left margin next to
  records that do not have a match.  By default, an exclamation  point
  is used as the change bar character.

  In HEXADECIMAL and OCTAL output mode, the change  bar  character  is
  ignored.   Instead,  the string "***CHANGE***" appears in the record
  header.

  You can control whether the change bar listing includes line numbers
  by  specifying  either NUMBER or NONUMBER.  If neither is specified,
  the default is controlled by the /[NO]NUMBER command qualifier.

  To specify  both  a  change  bar  character  and  either  NUMBER  or
  NONUMBER,  separate the options with a comma and enclose the list in
  parentheses, for example, /CHANGE_BAR=($,NUMBER).

 /COMMENT_DELIMITER[=(delimiter[,...])]

 Specifies one or more comment delimiters.   This  qualifier  is  used
  with  or  without  the  /IGNORE=COMMENTS qualifier to indicate which
  comments are to be ignored.

  You can specify a comment delimiter either by listing the  character
  itself or by using one of the following keywords:

       Keyword            Character

       COLON              Colon (:)

       COMMA              Comma (,)

       EXCLAMATION        Exclamation point (!)

       FORM_FEED          Form feed

       LEFT               Left bracket ([)

       RIGHT              Right bracket (])

       SEMI_COLON         Semicolon (;)

       SLASH              Slash (/)

       SPACE              Space

       TAB                Horizontal tab

  You can specify up to 32 comment characters.  If  you  specify  only
  one delimiter, you can omit the parentheses.

  When you specify a keyword, you must type at  least  the  first  two
  letters  of  the  keyword,  since  single  letters  are  treated  as
  delimiters.   Lowercase  letters  are   automatically   changed   to
  uppercase  unless they are enclosed in quotation marks.  If both the
  uppercase and lowercase  forms  of  a  letter  are  to  be  used  as
  delimiters,  the  letter  must be specified twice, once in uppercase
  and once in lowercase.  Non-alphanumeric  characters  (for  example,
  "!" and ",") must be enclosed in quotation marks.

  If you do not include either a comment character or a  keyword  with
  the  /COMMAND_DELIMITER  qualifier,  DIFFERENCES  assumes  a default
  comment character based on the file type.  For some file types  (COB
  and  FOR),  the  default  comment  characters  are  considered valid
  delimiters only if they appear  in  the  first  column  of  a  line.
  Multicharacter comment delimiters are not allowed.

 /IGNORE=(option[,...])

 Specifies that one or more special characters, strings, or records be
  ignored  during the comparison.  The /IGNORE qualifier also controls
  whether the comparison  records  are  output  to  the  listing  file
  exactly  as  they  appeared  in the input file or as edited records.
  The option parameter refers either to a character or a keyword.  The
  following keywords are valid options for the /IGNORE qualifier:

  BLANK_LINES         Blank lines between data lines.

  COMMENTS            Data that follow a comment delimiter.  (Use  the
                      /COMMENT_DELIMITER qualifier to designate one or
                      more non-default comment delimiters.)

  FORM_FEEDS          Form feed characters.

  HEADER[=n]          First n records beginning with  a  record  whose
                      first  character  is  a  form  feed.  (The first
                      record is not ignored if the only  character  it
                      contains is a form feed.) The default value of n
                      is 2.

  TRAILING_SPACES     Space and tab characters at the end of a line of
                      data.

  SPACING             Multiple spaces or tabs within  lines  of  data.
                      (Each  set  of  contiguous  spaces  or  tabs  is
                      replaced by a single space.)

  Each data line is checked  for  COMMENTS,  FORM_FEEDS,  HEADER,  and
  SPACING   before   it   is   tested  for  TRAILING_SPACES  and  then
  BLANK_LINES.   Therefore,  if  you  direct  DIFFERENCES  to   ignore
  COMMENTS, TRAILING_SPACES, and BLANK_LINES, it will totally ignore a
  record that contains several spaces or blank  lines  followed  by  a
  comment.

  By default, the DIFFERENCES command compares every character in each
  file  and  reports  all  differences.  Also, by default, DIFFERENCES
  lists records  in  the  output  file  with  all  ignored  characters
  deleted.

  Although output records can contain any characters  that  appear  in
  the  input files, you can choose to have output records formatted as
  follows:

       Character                           Formatted Output

       Tab (CTRL/I)                        1-8 spaces

       RET (CTRL/M)                        <CR>

       Line feed (CTRL/J)                  <LF>

       Vertical tab (CTRL/K)               <VT>

       Form feed (CTRL/L)                  <FF>

       Other nonprinting characters        . (period)

  If you specify /PARALLEL, output formatting is always performed.

  You can choose how you want the records to appear by specifying  one
  of the following keywords with the /IGNORE qualifier:

  EDITED              Output records are listed with  ignored  strings
                      deleted.

  EXACT               Output records are listed exactly as they appear
                      in the input file.

  PRETTY              Output records are formatted.

 /MATCH=size

 Specifies the number of records that constitutes a match.

  By default, after DIFFERENCES finds unmatched  records,  it  assumes
  that  the  files  once  again  match after it finds three sequential
  records that match.   Use  the  /MATCH  qualifier  to  override  the
  default match size of 3.

  You can increase the /MATCH value if you feel  that  DIFFERENCES  is
  incorrectly matching sections of the master and revision input files
  after it has detected a difference.

 /MAXIMUM_DIFFERENCES=n

 Specifies that DIFFERENCES is to terminate after a  specified  number
  of unmatched records has been found.

  The number of unmatched records is determined by finding the maximum
  number  of difference records for each difference section and adding
  them together.

  If DIFFERENCES reaches the maximum number of  differences  that  you
  specify, it will output only those records that were detected before
  the maximum was reached.  Also, it will output, at most, one listing
  format and return a warning message.

  By default, there is no maximum number of differences.  All  records
  in the specified input files are compared.

 /MERGED[=n]

 Requests that the output file contain a merged list  of  differences.
  The  value  n  indicates the number of matched records to list after
  each list of unmatched records; it should be a decimal  number  less
  than  or  equal  to  the  size  of  a  match  (see  the  /MATCH=size
  qualifier).

  By default, DIFFERENCES produces a merged listing with  one  matched
  record  listed  after  each  set  of  unmatched  records  (that  is,
  /MERGED=1).

  Use the /MERGED qualifier to override the default value of n, or  to
  include a merged listing with other types of output.

 /MODE=(radix[,...])

 Specifies the format of the output listing.  You can request that the
  output  be  formatted  in  one or more radix modes by specifying the
  following keywords:

       ASCII
       HEXADECIMAL
       OCTAL

  Enclose the keywords in parentheses.  You can truncate any of  these
  keywords to one or more characters.

  By default, DIFFERENCES writes the output file  in  ASCII.   If  you
  specify  more  than  one radix, the output listing contains the file
  comparison in each specified radix.  When you specify  two  or  more
  radix modes, separate them with commas.

  If you specify the /PARALLEL or /SLP qualifier, the /MODE  qualifier
  is ignored for that listing form.

 /NUMBER (default)
 /NONUMBER

  Controls whether line numbers are to be generated for records in the
  listing.

 /OUTPUT[=file-spec]

 Defines an output file to receive the output difference list.  If you
  omit  the  /OUTPUT  qualifier,  the output is written to the current
  SYS$OUTPUT device.  If you use the /OUTPUT qualifier without a  file
  specification,  the  output is directed to a file with the same name
  as the master file with the file type DIF.

  When you specify /OUTPUT, you can control the  defaults  applied  to
  the  output  file  specification  as described in Section 2.4 of the
  VAX/VMS DCL Concepts Manual.  The default output file type is DIF.

  No wildcard characters are allowed in the file specification.

 /PARALLEL[=n]

 Requests that the output file contain a parallel list of differences.
  The  value n indicates the number of matched records to output after
  each list of unmatched records; it should be a decimal  number  less
  than  or  equal  to  the  size  of  the  match  (see the /MATCH=size
  qualifier).

  By default, DIFFERENCES does not list records  after  each  list  of
  unmatched records.  Also by default, DIFFERENCES creates only a list
  of merged differences.

 /SEPARATED[=(input-file[,...])]

 Requests that the output file contain sequential lists  of  unmatched
  records  from  the  specified  input  files.   You can designate the
  desired input files by specifying the following keywords:

       MASTER
       REVISION

  If you specify only one input file, you can omit the parentheses.

  If you specify the  /SEPARATED  qualifier  without  designating  any
  input  files,  DIFFERENCES will generate a separate listing for each
  input file.

  By default, DIFFERENCES creates only a merged list of differences.

 /SLP

 Requests that DIFFERENCES produce an output file suitable  for  input
  to  the  SLP  editor.   If  you  use  the /SLP qualifier, you cannot
  specify any of  the  following  output  file  qualifiers:   /MERGED,
  /PARALLEL, /SEPARATED, or /CHANGE_BAR.

  Use the output file produced by the SLP qualifier as input to SLP to
  update the master input file, that is, to make the master input file
  match the revision input file.

  When you specify /SLP and you do not  specify  /OUTPUT,  DIFFERENCES
  writes  the  output  file  to  a file with the same file name as the
  master input file with the file type DIF.

 /WIDTH=n

 Specifies the width of lines in the output listing.

  By default, output is 132 characters wide, unless output is directed
  to  the terminal.  In that case, the output line width is controlled
  by the terminal line width.  Use the SET TERMINAL command to  change
  the terminal line width.

 /WINDOW=size

 Controls the number of records to search before listing a  record  as
  unmatched  and  continuing  with the next record in the master input
  file.

  The window size is the minimum size of a  differences  section  that
  will cause DIFFERENCES to lose synchronization between the two input
  files.

  By default, DIFFERENCES searches to the ends  of  both  input  files
  before listing a record as unmatched.

  1.   $ DIFFERENCES EXAMPLE.TXT

       ************
       File DISK1:[GEORGE.TEXT]EXAMPLE.TXT;2
           1   DEMONSTRATION
           2   OF V3.0 DIFFERENCES
           3   UTILITY
       ******
       File DISK1:[GEORGE.TEXT]EXAMPLE.TXT;1
           1   DEMONSTRATION
           2   OF VMS DIFFERENCES
           3   UTILITY
       ************

       Number of difference sections found: 1
       Number of difference records found: 2

       DIFFERENCES/MERGED=1-
              DISK1:[GEORGE.TEXT]EXAMPLE.TXT;2
              DISK1:[GEORGE.TEXT]EXAMPLE.TXT;1

  The DIFFERENCES command compares the contents of the two most recent
  versions  of  the file EXAMPLE.TXT in the current default directory.
  DIFFERENCES compares every character in every  record  and  displays
  the results at the terminal.