so () {
    [ -f "$1" ] && source "$1"
}

if [[ $0 == *bash ]]; then
    so "$HOME"/.subbash/export
    so "$HOME"/.subbash/shopt
fi

if [[ $- == *i* ]]; then
    so "$HOME"/.subbash/prompt
    so "$HOME"/.subbash/aliases
    so "$HOME"/.subbash/functions
    so "$HOME"/.subbash/completion
fi