change() {
    from=${1}
    shift
    while [ $# -gt 0 ]; do
        case ${1} in
            "to")
                shift
                to=${1} ;;
            "in")
                shift
                file=${1} ;;
        esac
        shift
    done

    if [ -n $from -a -n $file ]; then
        eval "sed -i 's%${from}%${to}%g' $file"
    else
        stop "poorly formed change statement"
    fi
}