#!/bin/sh

usage ()
{
    echo "Usage: $0 to_convert_from input_file.pdb output_file.pdb"
    echo "to_convert_from can be: CNS or PDB"
    exit 0
}

convert ()
{
    if [ x$1 == "xCNS" ]; then
	sed "s:\( \)\([A-Z][A-Z][A-Z] \)\([ ,A-Z]\)\(.\{50\}\)\([A-Z]\)\([A-Z]\):\6\2\5\4\5 :" $2 > $3
    elif [ x$1 == "xPDB" ]; then
	sed "s:\([ ,1-2]\)\([A-Z]\)\([A-Z][A-Z][A-Z] \)\([A-Z]\)\(.\{50\}[A-Z]\)\( \):\1 \3\4\5\2:" $2 > $3
    fi
}

if [ $# != 3 ]; then
    usage
fi

convert $1 $2 $3