SQL & PL/SQL

HI all,

please see the following script where the variable length is more than a 100 charecters...
When i run this in sqlplus with SERVEROUTPUT ON, i see the ouput being truncated to 100 charecters.

sql> ed
Wrote file afiedt.buf

  1  declare
  2     l_var varchar2(400);
  3  begin
  4     l_var := 'abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefgh
  5     dbms_output.put_line(length(l_var));
  6     dbms_output.put_line(l_var);
  7* end;
  8  /
130
abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuv

I think I am looking for a sqlplus "SET XXXX..." command, but my search has been futile so far.
Please advice.

Thanks,
John.