我安装了 Ubuntu 服务器 12.04，所以我没有 GUI。当我执行 ifconfig 命令时，我找不到我的内部 IP 地址。它说 inet 地址：127.0.0.1。
这是输出ifconfig -a：
eth0 link encap:Ethernet HWaddr 00:06:4f:4a:66:f0
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
eth1 link encap:Ethernet HWaddr 00:16:ec:05:c8:9c
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
lo Link encap:Local …如果我使用单引号将 awk 的 action 语句括起来，它会按预期工作：
$ dpkg -l | grep "linux\-[a-z]*\-" | awk {'print $2'}
linux-headers-3.13.0-27
linux-headers-3.13.0-27-generic
linux-headers-3.14.4-031404
linux-headers-3.14.4-031404-generic
linux-headers-generic
linux-image-3.13.0-27-generic
linux-image-3.14.4-031404-generic
linux-image-extra-3.13.0-27-generic
linux-image-generic
linux-libc-dev:i386
linux-sound-base
但是如果我使用双引号将它们括起来，它会打印整行而不是特定的列/字段：
$ dpkg -l | grep "linux\-[a-z]*\-" | awk {"print $2"}
ii linux-headers-3.13.0-27 3.13.0-27.50 all Header files related to Linux kernel version 3.13.0
ii linux-headers-3.13.0-27-generic 3.13.0-27.50 i386 Linux kernel headers for version 3.13.0 on 32 bit x86 SMP
ii linux-headers-3.14.4-031404 3.14.4-031404.201405130853 all Header files related to Linux kernel version 3.14.4
ii linux-headers-3.14.4-031404-generic 3.14.4-031404.201405130853 i386 …