The Bywater BASIC Interpreter (bwBASIC) implements a large superset of the ANSI Standard for Minimal BASIC (X3.60-1978) and a significant subset of the ANSI Standard for Full BASIC (X3.113-1987) in C.
apt install bwbasic
/usr/share/doc/bwbasic/README.gz
/usr/share/doc/bwbasic/examples
save "/home/user/file.bas"
load "/home/user/file.bas"