-tchar
Uses delimiter char to identify fields
-k n
sorts the nth field
-k m, n
Starts sort on mth field and ends sort on nth field
-k m.n
Stars sort on nth column of mth field
-u
removes repeated lines
-n
sorts numerically
-r
reverses sort order
-f
Folds lowercase to equivalent uppercase
-m list
merges sorted files in list
-c
checks if file is sorted
-o filename
places output in file filename