Linux 下常用的字符串 处理命令 记录 awk sed cut grep

1. awk
详细参数说明
awk '{print $3,$4}' /proc/net/arp
把arp文件的第三行和第四行，打印出来，可以重定向到文件

root@OpenWrt:/tmp# awk '{print $3,$4}' /proc/net/arp >/tmp/net_arp_list
root@OpenWrt:/tmp# cat net_arp_list 
HW type
0x2 28:ed:6a:e9:ab:fb
0x2 00:e0:4c:68:00:03
0x2 a4:44:d1:d6:d2:3f
root@OpenWrt:/tmp# cd /tmp/
root@OpenWrt:/tmp# ls
802.mt7603e.log        extroot                net_arp_list
802.mt7612e.log        fastcgi.socket-0       overlay

root@OpenWrt:/tmp# cat /proc/net/arp 
IP address       HW type     Flags       HW address            Mask     Device
192.168.0.30     0x1         0x2         28:ed:6a:e9:ab:fb     *        br-lan
192.168.0.188    0x1         0x2         00:e0:4c:68:00:03     *        br-lan
192.168.0.250    0x1         0x2         a4:44:d1:d6:d2:3f     *        br-lan
root@OpenWrt:/tmp# awk '{print $3,$4}' /proc/net/arp 
HW type
0x2 28:ed:6a:e9:ab:fb
0x2 00:e0:4c:68:00:03
0x2 a4:44:d1:d6:d2:3f

2.cut
详细参数说明
cut -d ‘空格’ -f 1
以 ‘空格’ 为分隔符，选取第一个域里面的内容，输出

root@OpenWrt:/tmp# grep "28:ed:6a:e9:ab:fb" /tmp/net_arp_list 
0x2 28:ed:6a:e9:ab:fb
root@OpenWrt:/tmp# grep "28:ed:6a:e9:ab:fb" /tmp/net_arp_list | cut -d ' ' -f 1
0x2
root@OpenWrt:/tmp#