-n n   Split into n-line pieces.

-l n   Synonym for -n n, a nod to Unix's syntax.

-e expression
       File divisions occur at each line that matches a regular expression; see regexp(7).   Multiple  -e
       options  may  appear.   If  a  subexpression  of expression is contained in parentheses (...), the
       output file name is the portion of the line which matches the subexpression.

-f stem
       Use stem instead of x in output file names.

-s suffix
       Append suffix to names identified under -e.

-x     Exclude the matched input line from the output file.

-i     Ignore case in option -e; force output file names (excluding the suffix) to lower case.