for Markov Algorithm Online: https://mao.snuke.org/
$ pip3 install git+https://github.com/kmyk/markov-algorithm-interpreter
Also, you can just download markov_algorithm.py
and use it directly.
$ echo INPUT | markov FILE
For example,
$ cat append-s.txt
#!/usr/bin/env markov
sb:bs
s::
:s
$ echo bb | markov append-s.txt
ops = [('sb', False, 'bs'), ('s', True, ''), ('', False, 's')]
0: bb
1: sbb
2: bsb
3: bbs
3: bb
bb