#!/bin/bash
function levenshtein {
if [ "$#" -ne "2" ]; then
echo "Usage: $0 word1 word2" >&2
elif [ "${#1}" -lt "${#2}" ]; then
levenshtein "$2" "$1"
else
local str1len=$((${#1}))
local str2len=$((${#2}))
local d i j
for i in $(seq 0 $(((str1len+1)*(str2len+1)))); do
d[i]=0
done
for i in $(seq 0 $((str1len))); do
d[$((i+0*str1len))]=$i
done
for j in $(seq 0 $((str2len))); do
d[$((0+j*(str1len+1)))]=$j
done
for j in $(seq 1 $((str2len))); do
for i in $(seq 1 $((str1len))); do
[ "${1:i-1:1}" = "${2:j-1:1}" ] && local cost=0 || local cost=1
local del=$((d[(i-1)+str1len*j]+1))
local ins=$((d[i+str1len*(j-1)]+1))
local alt=$((d[(i-1)+str1len*(j-1)]+cost))
d[i+str1len*j]=$(echo -e "$del\n$ins\n$alt" | sort -n | head -1)
done
done
echo ${d[str1len+str1len*(str2len)]}
fi
}
while read str1 str2; do
lev=$(levenshtein "$str1" "$str2");
printf "$lev"
done
