如何查看DHCP分配的DNS地址？
ifconfig 不能显示它。
$ ifconfig -a
eth0 Link encap:Ethernet HWaddr 90:e6:ba:22:6a:f2
inet addr:192.168.1.111 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: fe80::92e6:baff:fe22:6af2/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:224856 errors:0 dropped:0 overruns:0 frame:0
TX packets:220040 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:166848627 (166.8 MB) TX bytes:20256333 (20.2 MB)
Interrupt:46 Base address:0x4000
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:5889 errors:0 dropped:0 overruns:0 frame:0
TX packets:5889 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0 …我已经添加了
sh /home/victor/startupAP.sh
into/etc/rc.local和startupAP.shcontains 语句需要sudo：
$ cat startupAP.sh
#!/bin/bash
sudo hostapd -B /etc/hostapd/hostapd.conf 2>&1 >/home/victor/startupap.log
#sudo ifconfig wlan1 192.168.0.1 netmask 255.255.255.0; sudo dhcpd wlan1 -pf /var/run/dhcp-server/dhcpd.pid; sudo bash -c "echo 1 >/proc/sys/net/ipv4/ip_forward"; sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
sudo ifconfig wlan1 192.168.0.1 netmask 255.255.255.0 2>&1 >>/home/victor/startupap.log
sudo dhcpd wlan1 -pf /var/run/dhcp-server/dhcpd.pid 2>&1 >>/home/victor/startupap.log
sudo bash -c "echo 1 >/proc/sys/net/ipv4/ip_forward" 2>&1 >>/home/victor/startupap.log
sudo iptables -t nat -A POSTROUTING -o eth0 -j …我想使用 extundelete 恢复主目录中的一些文件
http://sourceforge.net/projects/extundelete/
该工具在开始工作之前需要卸载设备，但我无法卸载/home：
$ sudo umount /home
umount: /home: not mounted
$ sudo echo 1 >/proc/sys/net/ipv4/ip_forward
bash: /proc/sys/net/ipv4/ip_forward: Permission denied
然后我尝试获得写入权限，也失败了。
$ sudo chmod a+wx /proc/sys/net/ipv4/ip_forward
chmod: changing permissions of `/proc/sys/net/ipv4/ip_forward': Operation not permitted
怎么了？