diff-highlight.sh

#!/bin/sh
##
## ~/bin/diff-highlight
##

set -u

if [ -n "${BASH+set}" ]; then
  shopt -s lastpipe 2>/dev/null ## Bash 4.2+ for `exec ... |exec ...`
fi

if type perl >/dev/null 2>&1; then
  if [ -n "${GIT_EXEC_PATH+set}" ]; then
    git_prefix="${GIT_EXEC_PATH%/*}/../share"
  else
    git_prefix="/usr/share"
  fi
  git_diff_highlight_dir=$(echo "${git_prefix}"/doc/*git*/contrib/diff-highlight)
  if [ -d "$git_diff_highlight_dir" ]; then
    diff_highlight() {
      exec perl \
	-I "$git_diff_highlight_dir" \
	-e '
	  use DiffHighlight;
	  $SIG{PIPE} = "DEFAULT";
	  DiffHighlight::highlight_stdin();
	  exit 0;
	' \
      ;
    }
  fi
fi

if [ -n "${GIT_EXEC_PATH+set}" ] && type diff_highlight >/dev/null 2>&1; then
  diff_highlight
  exit $?
fi

for n in diff-highlight colordiff; do
  for p in /usr/local/bin /usr/bin; do
    c="$p/$n"
    if [ -x "$c" ]; then
      if type nkf >/dev/null 2>&1; then
	exec nkf -x -m0 |exec "$c" "$@"
      else
	exec "$c" "$@"
      fi
      exit $?
    fi
  done
done

if type diff_highlight >/dev/null 2>&1; then
  diff_highlight
  exit $?
fi

exec cat