These routines add commands to the buffer or clear the buffer:
dbcmd – adds text to the command buffer. It may be called repeatedly to add multiple commands, or parts of commands. The text added with each successive call is concatenated to the earlier text.
dbfcmd – adds text to the command buffer using sprintf-type formatting. This routine is the same as dbcmd, except that it allows arguments to be substituted into the text.
dbfreebuf – clears the command buffer. The command buffer is automatically cleared before a batch of commands is entered. To clear it at other times or when the DBNOAUTOFREE option has been set, use dbfreebuf.