#!/bin/sh

if [ $# -ne 2 ] ; then
	echo "select -- count number of equal neighboring lines" >&2
	echo "Usage: select FILE1 FILE2" >&2
	exit 1
fi

awk -v file1="$1" -v file2="$2" '

BEGIN {
	while (getline one[onec++] <file1) {
	}
	while (getline two[twoc++] <file2) {
	}

	for (i=1; i<onec; i++) {
		a1 = one[i-1];
		a2 = one[i];
		if (a2 == "") {
			break;
		}
		for (j=1; j<twoc; j++) {
			b1 = two[j-1];
			b2 = two[j];
			if ((a1 == b1 && a2 == b2) \
			    || (a1 == b2 && a2 == b1)) {
				# printf("one(%d,%d) == two(%d,%d): %s,%s\n",
				# i, i+1, j, j+1, a1, a2)
				same++
				break
			}
		}
	}
	print same;
}
'