#!/bin/sh
# bcd.sh
# Steve Parker, 16 April 2002 steve@steve-parker.org
# Public Domain
# Convert Decimal to BCD
# eg: 9 becomes 1001
#     2 becomes 0010
#    92 becomes 1001 0010

convert_digit()
{
#######################################
## it would be possible to do this   ##
## mathematically, but since we will ##
## only ever have a single decimal   ##
## digit, let's just use case        ##
#######################################

#######################################
## depending on your OS and shell,   ##
## getting echo to not use a newline ##
## character may require either of:  ##
##    echo "0101 \c"                 ##
##    echo -en "0101 "               ##
#######################################
  case $1 in
    0) echo "0000 \c" ;;
    1) echo "0001 \c" ;;
    2) echo "0010 \c" ;;
    3) echo "0011 \c" ;;
    4) echo "0100 \c" ;;
    5) echo "0101 \c" ;;
    6) echo "0110 \c" ;;
    7) echo "0111 \c" ;;
    8) echo "1000 \c" ;;
    9) echo "1001 \c" ;;
    *) echo 
       echo "Invalid input $1, expected decimal digit"
       ;;
  esac
}

#################
## main script ##
#################

decimal=$1
stringlength=`echo $decimal | wc -c`
char=1

while [ "${char}" -lt "${stringlength}" ]
do
  convert_digit `echo $decimal|cut -c ${char}`
  char=`expr ${char} + 1`
done
echo