Linux / UNIX Shell: Sort IP Address

To sort a list of IP addresses in a Unix or Linux shell, you can use the sort command with the -t option to specify the field separator and the -k option to specify the field number.

For example, to sort a list of IP addresses stored in the file input.txt, you can use the following command:

sort -t . -k 1,1n -k 2,2n -k 3,3n -k 4,4n input.txt

This will sort the IP addresses in the input.txt file by their octets, with the first octet as the primary sort key and the fourth octet as the secondary sort key. The -n option specifies that the fields should be treated as numeric values.

You can use the -o option to save the sorted output to a new file. For example:

sort -t . -k 1,1n -k 2,2n -k 3,3n -k 4,4n -o output.txt input.txt

This will sort the IP addresses in the input.txt file and save the sorted output to the output.txt file.

It is important to note that the sort command treats each octet as a separate field, and will not correctly sort IP addresses that contain non-numeric characters or octets that are not separated by periods (.). To sort a list of IP addresses that contain non-numeric characters or octets that are not separated by periods, you may need to use a different approach.

For more information about the sort command and its options, you can consult the documentation for your specific Unix or Linux system.