Reverse order of a string

Question

I want to "reverse" the order of the four octets (bytes) that make up an ip address.

Suppose I have this ip:

202.168.56.32

I need to convert into:

32.56.168.202

and then ultimately remove the first octet in the reversed ip. Final result:

56.168.202

My attempts:

echo 202.168.56.32 | rev

But it's returning :

23.65.861.202

Answer 1

This should do the trick:

echo 202.168.56.32|awk -F. '{print $3"."$2"."$1}'

You could also do it with bash arrays:

ip=202.168.56.32
parts=(${ip//./ })
echo ${parts[2]}.${parts[1]}.${parts[0]}

Answer 2

或者您可以使用sed。

echo 202.168.56.32 | sed -e 's/\([0-9]*\)\.\([0-9]*\)\.\([0-9]*\)\.\([0-9]*\)/\4.\3.\2.\1/g'