Always use these options immediately after the sortcommand. 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.