Always use these options immediately after the sort command. For example
sort -n +1 -2 costs
sorts the data in field 2 of the file costs by its arithmetic value.
-d (Dictionary order) sort only uses
numbers, letters and blank spaces when sorting
the file.
-f (Fold in lower case) sort treats all lower-case
letters as if they were upper-case letters.
-i (Ignore non-printing characters) sort ignores
any characters that do not print.
-n (Numeric order) sort recognises the value of
numbers and sorts them in terms of their
value.
-r (Reverse order) sort reverses its default sort
order.