SQL> declare
  2    l_clob clob;
  3    l_file bfile := bfilename('UTL_DIR', 'story.txt');
  4  begin
  5    select chapter_text
  6    into l_clob
  7    from my_book_text
  8    where chapter_desc = 'Chapter 1'
  9    for update of chapter_text;
 10  
 11    dbms_lob.fileopen(l_file);
 12  
 13    dbms_lob.loadfromfile(l_clob, l_file, 13);
 14    commit;
 15  
 16    dbms_lob.fileclose(l_file);
 17  end;
 18  /

PL/SQL procedure successfully completed

SQL> select chapter_text from my_book_text
  2  /

CHAPTER_TEXT
--------------------------------------------------------------------------------
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SQL> set serveroutput on
SQL> 
SQL> declare
  2    l_clob clob;
  3  begin
  4    select chapter_text
  5    into l_clob
  6    from my_book_text
  7    where chapter_desc = 'Chapter 1';
  8  
  9    dbms_output.put_line(dbms_lob.substr(l_clob, 13, 1));
 10  end;
 11  /

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PL/SQL procedure successfully completed

SQL>