zeropad

#!/bin/sh

#   ZEROPAD - Pad numbers with zeros
#
#   Tem Behrens, FMRIB Image Analysis Group
#
#   Copyright (C) 2004 University of Oxford
#
#   SHCOPYRIGHT

Usage() {
echo ""
echo "Usage: zeropad <input> <length of output>"
echo "e.g. zeropad 1 4    gives 0001"
echo ""
exit 1
}

[ "$1" = "" ] && Usage
[ "$2" = "" ] && Usage


i=`echo $1 | wc -c`;
j=0;
k=` expr $2 - $i`;
k=` expr $k + 1`;
num=$1;
while [ "$j" -lt "$k" ];do
num=0$num;
j=` expr $j + 1`
done
echo $num