jwdiff

#!/bin/bash
##
## jwdiff: Display word differences between Japanese text files
## Copyright (c) 2013 SATOH Fumiyasu @ OSS Technology Corp., Japan
##               <https://github.com/fumiyas/home-commands/blob/master/jwdiff>
##               <https://fumiyas.github.io/>
##               <http://www.osstech.co.jp/>
##
## License: GNU General Public License version 3
##

set -u

pdie() {
  echo "$0: ERROR: $1"
  exit ${2-1}
}

wakati() {
  expand ${1+"$1"} \
    |mecab \
      --node-format '%M\t' \
      --eos-format '\n' \
  ;
}

usage="\
Usage:
  ${0##*/} [OPTION] FILE1 FILE2
  ${0##*/} -d [OPTION]

Options:
  See wdiff(1) manpage
"

if [[ ${1-} = -d ]] || [[ ${1-} = --diff-input ]]; then
  wakati |wdiff "$@" |sed 's/	//g'
else
  if [[ $# -lt 2 ]]; then
    echo "$usage" 1>&2
    exit 1
  fi

  args=("$@")
  args_last=$((${#args[@]} - 1))
  file2="${args[$args_last]}";
  unset args[$args_last]
  let args_last--
  file1="${args[$args_last]}";
  unset args[$args_last]

  [[ -f $file1 ]] || [[ -L $file1 ]] || pdie "No such file: $file1"
  [[ -f $file2 ]] || [[ -L $file2 ]] || pdie "No such file: $file2"

  wdiff \
    ${args+"${args[@]}"} \
    <(wakati "$file1") \
    <(wakati "$file2") \
    |sed 's/	//g' \
  ;
fi