numbers to words

$ cat n2w
#! /bin/bash

[ $# -eq 1 ] && expr "$1" : '^[0-9]*$' >/dev/null 2>&1 || {
  echo 1>&2 "Command format is \"$(basename $0) n\"."
  exit 1
  }

#     0  1  2   3   4   5   6   7    8   9
d2l=( '' '' abc def ghi jkl mno pqrs tuv wxyz )

n=$1
p=''
while (( n > 0 )) ; do
  (( d = n % 10 ))
  (( n = n/10 ))
  if (( d > 1 )) ; then
    p="[${d2l[$d]}]$p"
  fi
done

grep -i "^$p\$" /usr/share/dict/american-english

$ ./n2w 228
act
bat
cat

$ ./n2w 96737
words

$ ./n2w 6862377
Numbers
numbers

$ ./n2w 2244744

$ ./n2w 4744

$ ./n2w 2243224

$ ./n2w 3224
each

$