Try using like this:-
sort -k1,1 -k4,4n
- -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.