cdif | sdif-tools

NAME

cdif - word context diff

VERSION

Version 4.38

SYNOPSIS

cdif [option] file1 file2

cdif [option] [diff-data]

Options:

    -c, -Cn         context diff
    -u, -Un         unified diff
    -i              ignore case
    -b              ignore space change
    -w              ignore whitespace
    -t              expand tabs

    --diff=command      specify diff command
    --subdiff=command   specify backend diff command
    --stat              show statistical information
    --colormap=s        specify color map
    --sdif              sdif friendly option
    --[no]color         color or not            (default true)
    --[no]256           ANSI 256 color mode     (default true)
    --[no]cc            color command line      (default true)
    --[no]mc            color diff mark         (default true)
    --[no]tc            color normal text       (default true)
    --[no]uc            color unknown text      (default true)
    --[no]old           print old text          (default true)
    --[no]new           print new text          (default true)
    --[no]mrg           print merged text       (default true)
    --[no]command       print diff command line (default true)
    --[no]unknown       print unknown line      (default true)
    --[no]mark          print mark or not       (default true)
    --[no]prefix        read git --graph output (default true)
    --unit=s            word/letter/char/mecab  (default word)
    --[no]mecab         use mecab tokenizer     (default false)
    --prefix-pattern    prefix pattern
    --visible char=?    set visible attributes
    --[no]lenience      suppress unexpected input warning (default true)
    --lxl               compare input data line-by-line

DESCRIPTION

cdif is a post-processor of the Unix diff command. It highlights deleted, changed and added words based on word context (–unit=word by default). If you want to compare text character-by-character, use option –unit=char. Option –unit=mecab tells to use external mecab command as a tokenizer for Japanese text.

If single or no file is specified, cdif reads that file or STDIN as an output from diff command. In addition to normal diff, context diff, and unified (combined) diff, the git(1)-compatible conflict marker format is supported as input format.

Lines those don’t look like diff output are simply ignored and printed.

STARTUP and MODULE

cdif utilizes Perl Getopt::EX module, and reads ~/.cdifrc file if available when starting up. You can define original and default option there. Next line enables –mecab option and add crossed-out effect for deleted words.

option default --mecab --cm DELETE=+X

Modules under App::cdif can be loaded by -M option without prefix. Next command load App::cdif::colors module.

$ cdif -Mcolors

You can also define options in module file. Read `perldoc Getopt::EX::Module` for detail.

COLOR

Each lines are displayed in different colors. Each text segment has own labels, and color for them can be specified by –colormap option. Read `perldoc Getopt::EX::Colormap` for detail.

Standard module -Mcolors is loaded by default, and define several color maps for light and dark screen. If you want to use CMY colors in dark screen, place next line in your ~/.cdifrc.

option default --dark-cmy

Option –autocolor is defined in default module to call Getopt::EX::termcolor module. It sets –light or –dark option according to the brightness of the terminal screen. You can set preferred color in your ~/.cdifrc like:

option --light --cmy
option --dark  --dark-cmy

Automatic setting is done by Getopt::EX::termcolor module and it works with macOS Terminal.app and iTerm.app, and other XTerm compatible terminals. This module accept environment variable TERM_BGCOLOR as a terminal background color. For example, use 000 or #000000 for black and 555 or #FFFFFF for white.

Option –autocolor is set by default, so override it to do nothing to disable.

option --autocolor --nop

EXIT STATUS

cdif always exit with status zero unless error occurred.

OPTIONS

-[cCuUibwtT]

Almost same as diff command.
–unit=[word,letter,char,mecab,0,``]
–by=[word,letter,char,mecab,0,``]

Specify the comparing unit. Default is word and compare each line word-by-word. Specify char if you want to compare them character-by-character. Unit letter is almost same as word but does not include underscore.

When mecab is given as an unit, mecab command is called as a tokenizer for non-ASCII text. ASCII text is compared word-by-word. External mecab command has to been installed.

If you give empty string like --unit=, or 0, cdif does not compare text in any way. You’ll still get colorization effect.
–mecab

Shortcut for –unit=mecab.
–diff=command

Specify the diff command to use.
–subdiff=command

Specify the backend diff command to get word differences. Accept normal and unified diff format.

If you want to use git diff command, don’t forget to set -U0 option.
```
  --subdiff="git diff -U0 --no-index --histogram"
```
–[no-]color

Use ANSI color escape sequence for output.

–colormap=colormap, –cm=colormap

Basic colormap format is :

  FIELD=COLOR

where the FIELD is one from these :

  COMMAND  Command line
  OMARK    Old mark
  NMARK    New mark
  UTEXT    Same text
  OTEXT    Old text
  NTEXT    New text
  OCHANGE  Old change part
  NCHANGE  New change part
  APPEND   Appended part
  DELETE   Deleted part

and additional Common and Merged FIELDs for git-diff combined format.

  CMARK    Common mark
  CTEXT    Common text
  MMARK    Merged mark
  MTEXT    Merged text

You can make multiple fields same color joining them by = :

  FIELD1=FIELD2=...=COLOR

Also wildcard can be used for field name :

  *CHANGE=BDw

Multiple fields can be specified by repeating options

  --cm FILED1=COLOR1 --cm FIELD2=COLOR2 ...

or combined with comma (,) :

  --cm FILED1=COLOR1,FIELD2=COLOR2, ...

Color specification is a combination of single uppercase character representing 8 colors :

  R  Red
  G  Green
  B  Blue
  C  Cyan
  M  Magenta
  Y  Yellow
  K  Black
  W  White

and alternative (usually brighter) colors in lowercase :

  r, g, b, c, m, y, k, w

or RGB values and 24 grey levels if using ANSI 256 or full color terminal :

  (255,255,255)      : 24bit decimal RGB colors
  #000000 .. #FFFFFF : 24bit hex RGB colors
  #000    .. #FFF    : 12bit hex RGB 4096 colors
  000 .. 555         : 6x6x6 RGB 216 colors
  L00 .. L25         : Black (L00), 24 grey levels, White (L25)

or color names enclosed by angle bracket :

  <red> <blue> <green> <cyan> <magenta> <yellow>
  <aliceblue> <honeydue> <hotpink> <moccasin>
  <medium_aqua_marine>

with other special effects :

  D  Double-struck (boldface)
  I  Italic
  U  Underline
  S  Stand-out (reverse video)

Above color spec is simplified summary so if you want complete information, read Getopt::EX::Colormap.

Defaults are :

  COMMAND => "555/222E"
  OMARK   => "CS"
  NMARK   => "MS"
  UTEXT   => ""
  OTEXT   => "C"
  NTEXT   => "M"
  OCHANGE => "K/445"
  NCHANGE => "K/445"
  DELETE  => "K/544"
  APPEND  => "K/544"

  CMARK   => "GS"
  MMARK   => "YS"
  CTEXT   => "G"
  MTEXT   => "Y"

This is equivalent to :

  cdif --cm 'COMMAND=555/222E,OMARK=CS,NMARK=MS' \
       --cm 'UTEXT=,OTEXT=C,NTEXT=M,*CHANGE=BD/445,DELETE=APPEND=RD/544' \
       --cm 'CMARK=GS,MMARK=YS,CTEXT=G,MTEXT=Y'

–colormap=&func
–colormap=sub{...}

You can also set the name of perl subroutine name or definition to be called handling matched words. Target word is passed as variable $_, and the return value of the subroutine will be displayed.

Next option produces wdiff-like formatted output.
```
  --cm '*'= \
  --cm DELETE=OCHANGE='sub{"[-$_-]"}' \
  --cm APPEND=NCHANGE='sub{"{+$_+}"}'
```
See “FUNCTION SPEC” in Getopt::EX::Colormap for detail.
–[no-]cc, –[no-]commandcolor
–[no-]mc, –[no-]markcolor
–[no-]tc, –[no-]textcolor
–[no-]uc, –[no-]unknowncolor

Enable/Disable using color for the corresponding field.
–sdif

Disable options appropriate to use for sdif’s input: –commandcolor, –markcolor, –textcolor and –unknowncolor.
–[no-]old, –[no-]new, –[no-]mrg

Print or not old/new/mrg text in diff output.
–[no-]command

Print or not command lines preceding diff output.
–[no-]unknown

Print or not lines not look like diff output.
–[no-]mark

Print or not marks at the top of diff output lines. At this point, this option is effective only for unified diff.

Next example produces the output exactly same as new except visual effects.
```
  cdif -U100 --no-mark --no-old --no-command --no-unknown old new
```
These options are prepared for watchdiff(1) command.
–[no-]prefix

Understand prefix for diff output including git –graph option. True by default.
–prefix-pattern=pattern

Specify prefix pattern in regex. Default pattern is:
```
  (?:\| )*(?:  )*
```
This pattern matches git graph style and whitespace indented diff output.

–visible charname=[0,1]

Set visible attribute for specified characters. Visible character is converted to corresponding Unicode symbol character. Default visible: nul, bel, bs, vt, np, cr, esc, del. Default invisible: ht, nl, sp.

  NAME  CODE  Unicode NAME                      DEFAULT
  ----  ----  --------------------------------  -------
  nul   \000  SYMBOL FOR NULL                   YES
  soh   \001  SYMBOL FOR SOH*                   YES
  bel   \007  SYMBOL FOR BELL                   YES
  bs    \010  SYMBOL FOR BACKSPACE              YES
  ht    \011  SYMBOL FOR HORIZONTAL TABULATION  NO
  nl    \012  SYMBOL FOR NEWLINE                NO
  vt    \013  SYMBOL FOR VERTICAL TABULATION    YES
  np    \014  SYMBOL FOR FORM FEED              YES
  cr    \015  SYMBOL FOR CARRIAGE RETURN        YES
  esc   \033  SYMBOL FOR ESCAPE                 YES
  sp    \040  SYMBOL FOR SPACE                  NO
  del   \177  SYMBOL FOR DELETE                 YES

Multiple characters can be specified at once, by assembling them by comma (,) like --visible ht=1,sp=1; or connecting them by equal sign (=) like --visible ht=sp=1. Character name accept wildcard; --visible '*=1'.

sdif command also support –visible option for horizontal tab with better visibility.

–stat

Print statistical information at the end of output. It shows number of total appended/deleted/changed words in the context of cdif. It’s common to have many insertions and deletions of newlines because of text filling process. So normal information is followed by modified number which ignores insert/delete newlines.
–[no-]lenience

Suppress warning message for unexpected input from diff command. True by default.
–linebyline, –lxl

Compare input data line-by-line. Consider the inputs as pairs of two lines each, and output the result of comparing each two lines.

Suppose you have a document with old and new text on lines beginning with OLD: and NEW: labels.
```
  OLD: this is old text
  NEW: and this is updated document
```
Only this old/new part can be compared using greple’s -Mtee module as follows.
```
  greple -Mtee cdif --lxl -- --cm=N -GE '^OLD: (.*\n)^NEW: (.*\n)'
```
-Mtee module sends matched parts to the filter command and replace them by its result. Consult App::Greple::tee for detail.

You can use teip(1) command as well.
```
  teip -g '^(OLD|NEW):' -- cdif --lxl
```

GIT

See `perldoc App::sdif` how to use related commands under the GIT environment.

ENVIRONMENT

CDIFOPTS

Environment variable CDIFOPTS is used to set default options.
LESS
LESSANSIENDCHARS

Since cdif produces ANSI Erase Line terminal sequence, it is convenient to set less command understand them.
```
  LESS=-cR
  LESSANSIENDCHARS=mK
```

AUTHOR

Kazumasa Utashiro

LICENSE

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

BUGS

cdif is naturally not very fast because it uses normal diff command as a back-end processor to compare words.