open file_name
open(file_name)
open open_file_number, file_name
open(open_file_number, file_name)
openb file_name
openb(file_name)
openb open_file_number, file_name
openb(open_file_number, file_name)

Opens a file for reading and writing. The file_name is specified as a string, and may be an absolute or relative path. If the file number is not specified file number zero (0) will be used.
Openb opens the file in a “binary safe” mode. This type of file open is recommended for files where the Readbyte and Writebyte statements are used for input/output.

BASIC256 may have up to 8 files open at a single time. The files are numbered from 0 to 7. Opening a file to a number while another is already open to that number will close the open file.