我在ubuntu安装了一个 电脑清扫工具，不小心把无线网卡驱动卸载掉了。我的无线网卡型号是：Realtek Device b723. 我用 lspci -vnn 命令得到如下信息：
05:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. Device [10ec:b723]
Subsystem: Lenovo Device [17aa:b728]
Flags: bus master, fast devsel, latency 0, IRQ 11
I/O ports at 3000 [size=256]
Memory at f1c00000 (64-bit, non-prefetchable) [size=16K]
Capabilities: [40] Power Management version 3
Capabilities: [50] MSI: Enable- Count=1/1 Maskable- 64bit+
Capabilities: [70] Express Endpoint, MSI 00
Capabilities: [100] Advanced Error Reporting
Capabilities: [140] Device Serial Number 00-23-b7-fe-ff-4c-e0-00
Capabilities: [150] Latency Tolerance Reporting
Capabilities: [158] #1e
Kernel modules: wl
用 ifconfig -a 没有发现wlan0。 我在网上搜了一些资料，发现一直不能成功安装，在这里求助各位大神帮帮小弟，小弟感激不尽！！！
