Commodore 128 System Manual page 245

APPEND
Append new data to the end of a sequential file.
APPEND #logical file number,"filename"[,Ddrive number]
[<0N | ,>Udevice]
This command opens the file having the specified filename, and
positions the pointer at the end of the file. Subsequent PRINT#
(write) statements will cause data to be appended to the end of
this file. Default values for drive number and device number are 0
and 8 respectively.
Variables or Expressions used as filenames must be enclosed
within parentheses.
EXAMPLES:
APPEND # 8 , "MYFILE"
OPEN logical file 8 called " MYFILE" for appending with
subsequent PRINT # statements.
APPEND # 7, (A$),D0,U9
OPEN logical file named by the variable in A$ on drive 0, device
number 9 and prepare to APPEND.
AUTO
Enable/disable automatic line numbering
AUTO [line#]
This command turns on the automatic line-numbering feature.
This eases the job of entering programs, by automatically typing
the line numbers for the user. As each program line is entered by
pressing RETURN, the next line number is printed on the screen,
and the cursor is positioned on the second space to the right of
the line number. The line number argument refers to the desired
increment between line numbers. AUTO without an argument
turns off the auto line numbering, as does RUN. This statement
can be used only in direct mode (outside of a program).
17-3