DECLARE
 err_code      number       := Error_code; 
 err_text      varchar2(80) := Error_text; 
 f_buffer      varchar2(5000) := null; 

 in_file_1 TEXT_IO.FILE_TYPE; 
 
 DIR1          VARCHAR2(5000); 
  
BEGIN 

DIR1 := :blk_save.filedirectory||'/'||:blk_save.filename; 

/* I prepare the file in writing */ 
IN_FILE_1 := TEXT_IO.FOPEN(DIR1,'w'); 

/* I prepare head */
f_buffer := '------------------------------------------------';    
TEXT_IO.put_line(in_file_1, f_buffer);
f_buffer := '-----  List of Users  '||to_char(sysdate,'dd-mon-yyyy hh24:mi:ss')||' -----';    
TEXT_IO.put_line(in_file_1, f_buffer);
f_buffer := '------------------------------------------------';    
TEXT_IO.put_line(in_file_1, f_buffer);
TEXT_IO.fclose(in_file_1); 

ecc... ecc...
END;