packages icon



            SPIFF(1)                                                           SPIFF(1)
                                         February 2, 1988



            NAME
                 spiff - make controlled approximate comparisons between files

            SYNOPSIS
                 spiff [ -s script ] [ -f sfile ] [ -bteviqcdwm ] [ -a | -r value ]
                 -value file1 file2

            DESCRIPTION
                 Spiff compares the contents of file1 and file2 and prints a
                 description of the important differences between the files.  White
                 space is ignored except to separate other objects.  Spiff maintains
                 tolerances below which differences between two floating point numbers
                 are ignored. Differences in floating point notation (such as 3.4 3.40
                 and 3.4e01) are treated as unimportant.  User specified delimited
                 strings (i.e. comments) can also be ignored.  Inside other user
                 specified delimited strings (i.e. quoted strings) whitespace can be
                 significant.

                 Spiff's operation can be altered via command line options, a command
                 script, and with commands that are embedded in the input files.

                 The following options affect spiff's overall operation.

                 -q   suppresses warning messages.

                 -v   use a visually oriented display.  Works only in MGR windows.

                 Spiff has several flags to aid differencing of various programming
                 languages.  See EXAMPLES for a detailed description of the effects of
                 these flags.

                 -C   treat the input files as C program source code.

                 -S   treat the input files as Bourne shell program source code.

                 -F   treat the input files as Fortran program source code.

                 -M   treat the input files as Modula-2 program source code.

                 -L   treat the input files as Lisp program source code.

                 By default, the output looks somewhat similar in appearance to the
                 output of diff(1).  Lines with differences are printed with the
                 differences highlighted.  If stdout is a terminal, as determined by
                 isatty(), then highlighting uses standout mode as determined by
                 termcap.  If stdout is not a tty, then the underlining (via
                 underscore/backspace/char) is used to highlight differences.  The
                 following option can control the format of the ouput.

                 -t   produce output in terms of individual tokens.  This option is
                      most useful for debugging as the output produced is verbose to



                                               - 1 -       Formatted:  October 25, 2014






            SPIFF(1)                                                           SPIFF(1)
                                         February 2, 1988



                      the point of being unreadable.

                 The following option controls the differencing algorithm.

                 -e   compare each token in the files with the object in the same
                      ordinal position in the other file.  If the files have a
                      different number of objects, a warning message is printed and the
                      objects at the end of the longer file are ignored.  By default,
                      spiff uses a Miller/Myers algorithm to find a minimal edit
                      sequence that will convert the contents of the first file into
                      the second.

                 -<decimal-value>
                      sets a limit on the total number of insertions and deletions that
                      will be considered.  If the files differ by more than the stated
                      amount, the program will give up, print a warning message, and
                      exit.

                 The following options control the command script.  More than one of
                 each may appear at at time. The commands accumulate.

                 -f sfile
                      a command script to be taken from file sfile

                 -s command-script
                      causes the following argument to be taken as a command script.

                 The following options control how individual objects are compared.

                 -b   treat all objects (including floating point numbers) as literals.

                 -c   ignore differences between upper and lower case.

                 The following commands will control how the files are parsed.

                 -w   treat white space as objects.  Each white space character will be
                      treated as a separate object when the program is comparing the
                      files.

                 -m   treat leading sign characters ( + and - ) as separate even if
                      they are followed by floating point numbers.

                 -d   treat integer decimal numbers (such as 1987) as real numbers
                      (subject to tolerances) rather than as literal strings.

                 The following three flags are used to set the default tolerances.  The
                 floating-point-numbers may be given in the formats accepted by
                 atof(3).

                 -a floating-point-number
                      specifies an absolute value for the tolerance in floating point



                                               - 2 -       Formatted:  October 25, 2014






            SPIFF(1)                                                           SPIFF(1)
                                         February 2, 1988



                      numbers.  The flag -a1e-2 will cause all differences greater than
                      0.01 to be reported.

                 -r floating-point-number
                      specifies a relative tolerance. The value given is interpreted as
                      a fraction of the larger (in absolute terms) of the two floating
                      point numbers being compared.  Thus, the flag -r0.1 will cause
                      the two floating point numbers 1.0 and 0.9 to be deemed within
                      tolerance. The numbers 1.0 and 0.89 will be outside the
                      tolerance.

                 -i   causes differences between floating point numbers to be ignored.

                 If more than one -a, -r, or -i flag appear on the command line, the
                 tolerances will be OR'd together (i.e. any difference that is within
                 any of the tolerances will be ignored).

                 If no default tolerances is set on the command line, the program will
                 use a default tolerance of '-a 1e-10 -r 1e-10'.

            SCRIPT COMMANDS
                 A script consists of commands, one per line.  Each command consists of
                 a keyword possibly followed by arguments.  Arguments are separated by
                 one or more tabs or spaces.  The commands are:

                 literal BEGIN-STRING [END-STRING [ESCAPE-STRING]]
                      Specifies the delimiters surrounding text that is to be treated
                      as a single literal object. If only one argument is present, then
                      only that string itself is treated as a literal. If only two
                      arguments are present, they are taking as the starting and ending
                      delimiters respectively.  If three arguments are present, they
                      are treated as the start delimiter, end delimiter, and a string
                      that may be used to escape an instance of the end delimiter.

                 beginchar BEGINNING-OF-LINE-CHARACTER
                      Set the the beginning of line character for BEGIN-STRING's in
                      comments.  The default is '^'.

                 endchar END-OF-LINE-CHARACTER
                      Set the end of line character for END-STRING's in comments.  The
                      default is '$'.

                 addalpha NEW-ALPHA-CHARACTER
                      Add NEW-ALPHA-CHARACTER to the set of characters allowed in
                      literal strings.  By default, spiff parses sequences of
                      characters that begin with a letter and followed by zero or more
                      letters or numbers as a single literal token.  This definition is
                      overly restrictive when dealing with programming languages.  For
                      example, in the C programming language, the underscore character
                      is allowed in identifiers.




                                               - 3 -       Formatted:  October 25, 2014






            SPIFF(1)                                                           SPIFF(1)
                                         February 2, 1988



                 comment BEGIN-STRING [END-STRING [ESCAPE-STRING]]
                      Specifies the delimiters surrounding text that is to be be
                      ignored entirely (i.e. viewed as comments).  The operation of the
                      comment command is very similar to the literal command.  In
                      addition, if the END-STRING consists of only the end of line
                      character, the end of line will delimit the end of the comment.
                      Also, if the BEGIN-STRING starts with the beginning of line
                      character, only lines that begin with the BEGIN-STRING will be
                      ignored.

                 More than one comment specification and more than one literal string
                 specification may be specified at a time.

                 nestcom BEGIN-STRING [END-STRING [ESCAPE-STRING]]
                      Similar to the comment command, but allows comments to be nested.
                      Note, due to the design of the parser nested comments can not
                      have a BEGIN-STRING that starts with the beginning of line
                      character.

                 resetcomments
                      Clears the list of comment specifications.

                 resetliterals
                      Clears the list of literal specifications.

                 tol [aVALUE|rVALUE|i|d . . . [ ; aVALUE|rVALUE|i|d . . . ] . . . ]
                      set the tolerance for floating point comparisons. The arguments
                      to the tol command are a set of tolerance specifications
                      separated by semicolons.  If more than one a,r,d, or i appears
                      within a specification, then the tolerances are OR'd together
                      (i.e. any difference that is within any tolerance will be
                      ignored).  The semantics of a,r, and i are identical to the -a,
                      -r, and -i flags. The d means that the default tolerance (as
                      specified by the invocation options) should be used.  If more
                      than one specification appears on the line, the first
                      specification is applied to the first floating point number on
                      each line, the second specification to the second floating point
                      number one each line of the input files, and so on.  If there are
                      more floating point numbers on a given line of input than
                      tolerance specifications, the last specification is used
                      repeatedly for all remaining floating point numbers on that line.

                 command STRING
                      lines in the input file that start with STRING will be
                      interpreted as command lines. If no "command" is given as part of
                      a -s or -f then it will be impossible to embed commands in the
                      input files.

                 rem





                                               - 4 -       Formatted:  October 25, 2014






            SPIFF(1)                                                           SPIFF(1)
                                         February 2, 1988



                 #    used to places human readable remarks into a commands script.
                      Note that the use of the '#' character differs from other command
                      languages (for instance the Bourne shell).  Spiff will only
                      recognize the '#' as beginning a comment when it is the first
                      non-blank character on the command line.  A '#' character
                      appearing elsewhere will be treated as part of the command.
                      Cautious users should use 'rem'.  Those hopelessly addicted to
                      '#' as a comment character can have command scripts with a
                      familiar format.

                 Tolerances specified in the command scripts have precedence over the
                 tolerance specified on the invocation command line. The tolerance
                 specified in file1 has precedence over the tolerance specified in
                 file2.

            VISUAL MODE
                 If spiff is invoked with the -v option, it will enter an interactive
                 mode rather than produce an edit sequence.  Three windows will be put
                 on the screen.  Two windows will contain corresponding segments of the
                 input files.  Objects that appear in both segments will be examined
                 for differences and if any difference is found, the objects will be
                 highlighted in reverse video on the screen.  Objects that appear in
                 only one window will have a line drawn through them to indicate that
                 they aren't being compared with anything in the other text window. The
                 third window is a command window.  The command window will accept a
                 single tolerance specification (followed by a newline) in a form
                 suitable to the tol command.  The tolerance specified will then be
                 used as the default tolerance and the display will be updated to
                 highlight only those objects that exceed the new default tolerance.
                 Typing m (followed by a newline) will display the next screenfull of
                 text. Typing q (followed by a newline)  will cause the program to
                 exit.

            LIMITS
                 Each input files can be no longer that 10,000 line long or contain
                 more than 50,000 tokens. Longer files will be truncated.  No line can
                 be longer than 1024 characters.  Newlines will be inserted every 1024
                 character.

            EXAMPLES
                 spiff -e -d foo bar
                      this invocation (using exact match algorithm and treating integer
                      numbers as if they were floats) is very useful for examining
                      large tables of numbers.

                 spiff -0 foo bar
                      compare the two files, quitting after the first difference is
                      found.  This makes the program operate roughly like cmp(1).

                 spiff -0 -q foo bar
                      same as the above, but no output is produced.  The return code is



                                               - 5 -       Formatted:  October 25, 2014






            SPIFF(1)                                                           SPIFF(1)
                                         February 2, 1988



                      still useful.

                 spiff -w -b foo bar
                      will make the program operate much like diff(1).

                 spiff -a1e-5 -r0.001 foo bar
                      compare the contents of the files foo and bar and ignore all
                      differences between floating point numbers that are less than or
                      equal to 0.00001 or 0.1% of the number of larger magnitude.

                 tol a.01 r.01
                      will cause all differences between floating point numbers that
                      are less than or equal to 0.01 or 1% of the number of larger
                      magnitude to be ignored.

                 tol a.01 r.01 ; i
                      will cause the tolerance in the previous example to be applied to
                      the first floating point number on each line.  All differences
                      between the second and subsequent floating point numbers on each
                      line will be ignored.

                 tol a.01 r.01 ; i ; a.0001
                      like the above except that only differences between the second
                      floating point number on each line will be ignored. The
                      differences between third and subsequent floating point numbers
                      on each number will be ignored if they are less than or equal to
                      0.0001.

                      A useful script for examing C code is:
                      literal  "    "    \
                      comment  /*  */
                      literal  &&
                      literal  ||
                      literal  <=
                      literal  >=
                      literal  !=
                      literal  ==
                      literal  --
                      literal  ++
                      literal  <<
                      literal  >>
                      literal  ->
                      addalpha _
                      tol      a0

                      A useful script for shell programs is:
                      literal  '    '    \
                      comment  #    $
                      tol      a0





                                               - 6 -       Formatted:  October 25, 2014






            SPIFF(1)                                                           SPIFF(1)
                                         February 2, 1988



                      A useful script for Fortran programs is:
                      literal ' ' '
                      comment ^C $
                      tol     a0

                      A useful script for Modula 2 programs is:
                      literal ' '
                      literal " "
                      nestcom (* *)
                      literal :=
                      literal <>
                      literal <=
                      literal >=
                      tol     a0

                      A useful script for Lisp programs is:
                      literal " "
                      comment ; $
                      tol     a0

            DIAGNOSTICS
                 Spiff's exit status is 0 if no differences are found, 1 if differences
                 are found, and 2 upon error.

            BUGS
                 In C code, escaped newlines will appear as differences.

                 Comments are treated as token delimiters.

                 Comments in Basic don't work right.  The line number is not ignored.

                 Continuation lines in Fortran comments don't work.

                 There is no way to represent strings specified using a Hollerith
                 notation in Fortran.

                 In formated English text, hyphenated words, movements in pictures,
                 footnotes, etc.  will be reported as differences.

                 STRING's in script commands can not include whitespace.

                 Visual mode does not handle tabs properly.  Files containing tabs
                 should be run through expand(1) before trying to display them with
                 visual mode.

                 In visual mode, the text windows appear in a fixed size and font.
                 Lines longer than the window size will not be handled properly.

                 Objects (literal strings) that contain newlines cause trouble in
                 several places in visual mode.




                                               - 7 -       Formatted:  October 25, 2014






            SPIFF(1)                                                           SPIFF(1)
                                         February 2, 1988



                 Visual mode should accept more than one tolerance specification.

                 When using visual mode or the exact match comparison algorithm, the
                 program should do the parsing on the fly rather than truncating long
                 files.

            AUTHOR
                 Daniel Nachbar

            COPYRIGHT
                                  Copyright (c) 1988 Bellcore
                                      All Rights Reserved
                 Permission is granted to copy or use this program,
                 EXCEPT that it may not be sold for profit, the copyright
                 notice must be reproduced on copies, and credit should
                 be given to Bellcore where it is due.
                          BELLCORE MAKES NO WARRANTY AND ACCEPTS
                             NO LIABILITY FOR THIS PROGRAM.


            SEE ALSO
                 atof(3) isatty(2) diff(1) cmp(1) expand(1) mgr(1L)

                 "Spiff -- A Program for Making Controlled Approximate Comparisons of
                 Files", by Daniel Nachbar.

                 "A File Comparison Program" by Webb Miller and Eugene W. Myers in
                 Software - Practice and Experience, Volume 15(11), pp.1025-1040,
                 (November 1985).

























                                               - 8 -       Formatted:  October 25, 2014