Linux扩展正则表达式及sed生产环境用法

[root@centos6 ~]# ifconfig
eth1      Link encap:Ethernet  HWaddr 00:0C:29:35:DD:AB
inet addr:10.1.253.95  Bcast:10.1.255.255  Mask:255.255.0.0
inet6 addr: fe80::20c:29ff:fe35:ddab/64 Scope:Link
UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
RX packets:378023 errors:0 dropped:0 overruns:0 frame:0
TX packets:12444 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:46926222 (44.7 MiB)  TX bytes:1240063 (1.1 MiB)
eth2      Link encap:Ethernet  HWaddr 00:0C:29:35:DD:B5
inet addr:192.168.226.135  Bcast:192.168.226.255  Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fe35:ddb5/64 Scope:Link
UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
RX packets:2539 errors:0 dropped:0 overruns:0 frame:0
TX packets:225 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:281133 (274.5 KiB)  TX bytes:39650 (38.7 KiB)
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:65536  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:0
RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)
[root@centos6 ~]# ifconfig |awk -F '[: ]+' 'NR==2{print $4}'
10.1.253.95
[root@centos6 ~]# ifconfig
eth1      Link encap:Ethernet  HWaddr 00:0C:29:35:DD:AB
inet addr:10.1.253.95  Bcast:10.1.255.255  Mask:255.255.0.0
inet6 addr: fe80::20c:29ff:fe35:ddab/64 Scope:Link
UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
RX packets:379965 errors:0 dropped:0 overruns:0 frame:0
TX packets:12615 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:47097014 (44.9 MiB)  TX bytes:1264173 (1.2 MiB)

eth2      Link encap:Ethernet  HWaddr 00:0C:29:35:DD:B5
inet addr:192.168.226.135  Bcast:192.168.226.255  Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fe35:ddb5/64 Scope:Link
UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
RX packets:2541 errors:0 dropped:0 overruns:0 frame:0
TX packets:227 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:281535 (274.9 KiB)  TX bytes:40052 (39.1 KiB)

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:65536  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:0
RX bytes:0 (0.0 b)  TX bytes:0 (0.0 b)

[root@centos6 ~]# ifconfig |head -2
eth1      Link encap:Ethernet  HWaddr 00:0C:29:35:DD:AB
inet addr:10.1.253.95  Bcast:10.1.255.255  Mask:255.255.0.0
[root@centos6 ~]# ifconfig |head -2 |sed -r 's/^.*addr:(.*)  Bca.*$/\1/g'
eth1      Link encap:Ethernet  HWaddr 00:0C:29:35:DD:AB
10.1.253.95
[root@centos6 ~]# ifconfig |head -2|tail -1 |tr -s ' ' ':' |cut -d: -f4
10.1.253.95
[root@centos6 ~]#

[root@centos6 ~]# ifconfig |tr -cs '[:digit:].' '\n'|sort -t. -k4|tail -8
255.0.0.0
255.255.0.0
255.255.255.0
127.0.0.1
192.168.226.135
10.1.255.255
192.168.226.255
10.1.253.95
[root@centos6 ~]#

[root@centos6 ~]# df |grep "sd.*"
/dev/sda3      121455724 3990720 111288700   4% /
/dev/sda1         194241   34082    149919  19% /boot
/dev/sdb        20511356   44992  19417788   1% /mnt
[root@centos6 ~]# df |grep "sd.*"|tr -s ' ' ':'
/dev/sda3:121455724:3990720:111288700:4%:/
/dev/sda1:194241:34082:149919:19%:/boot
/dev/sdb:20511356:44992:19417788:1%:/mnt
[root@centos6 ~]# df |grep "sd.*"|tr -s ' ' ':'|cut -d: -f1,5
/dev/sda3:4%
/dev/sda1:19%
/dev/sdb:1%
[root@centos6 ~]# df |grep "sd.*"|tr -s ' ' ':'|cut -d: -f1,5|sort -nr
/dev/sdb:1%
/dev/sda3:4%
/dev/sda1:19%
[root@centos6 ~]#

[root@centos6 ~]# cat /etc/init.d/functions |tr -cs '[:alpha:]' '\n'|sort|uniq -c |sort-nr
83 if
77 then
75 pid
73 echo
72 fi
61 return
57 dev
54 file
50 n
46 local

[root@centos6 ~]# echo "/etc/init.d/functions"|sed -r 's#^(/.*/)[^/]+/?#\1#g'
/etc/init.d/
[root@centos6 ~]#

[root@centos6 ~]# echo "/etc/init.d/functions/"|sed -r 's#/.*/([^/]+)#\1#g'
functions/
[root@centos6 ~]#