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bashipv4parameter-expansion

How to replace the last octet in an IP adress using Bash?

I have a variable that contains an IP address.

ip=192.165.12.30

How can I replace the last octet with 0 so that it becomes as below?

ip=192.168.12.0
Solution

  • You can use a parameter expansion:

    $ ip=${ip%.*}.0
$ echo "$ip"
192.165.12.0