小编Aar*_*son的帖子

我似乎无法将字符类用于awk正则表达式，几乎完全按照此处的描述：

user@host:~$ awk -W version
mawk 1.3.3 Nov 1996, Copyright (C) Michael D. Brennan

compiled limits:
max NF             32767
sprintf buffer      2040
user@host:~$ echo "host.company.com has address 192.168.22.82" |awk '/^[a-zA-Z0-9.-]+ has address/ { print $4 }'
192.168.22.82
user@host:~$ echo "host.company.com has address 192.168.22.82" |awk '/^[[:alnum:].-]+ has address/ { print $4 }'
user@host:~$

有谁知道为什么第二个命令找不到地址字段？