sort -t . -k 3,3n -k 4,4n /path/to/file Where, -t . : Set field to . (dot) as our IPs separated by dot symbol -n : Makes the program sort according to numerical value -k opts: Sort data / fields using the given column number. For example, the option -k 2 made the program sort using the second column of data. The option -k 3,3n -k 4,4n sorts each column. First it will sort 3rd column and then 4th column.