如何在Linux中获得网络掩码

Question

I am trying to get the network mask using bash in that way:

192.168.1.0/x 

I tried with:

ip -o -f inet addr show | awk '/scope global/ {print $4}'

but the output is:

192.168.1.123/x

So this way doesn't work for me.

Answer 1

Since you are masking the last 8 bits, 192.168.1.123/24 is the same as 192.168.1.0/24. If you want the last byte to be 0 for cosmetic reasons, I would use sub() in awk:

ip -o -f inet addr show | awk '/scope global/{sub(/[^.]+\//,"0/",$4);print $4}'