function apply_cat {
    local out="$1"
    local src=("${@:2}")

    if apply_check "$out" "${src[@]}"; then
        log_skip "$out: skip cat: ${src[@]}"
    elif [ "$APPLY" = 0 ]; then
        log_noop "$out: noop cat: $tgt"
    else
        log_update "$out: cat ${src@}"

        cmd_apply "$out" \
            cat "${src[@]}"
    fi
}