Смотрите, что я нашел.
Real lambda support for bash (a functionally complete hack). Includes a set of
functions for functional programming,
list allocation and traversal,
futures,
complete closure serialization,
remote closure execution,
multimethods,
and
(вдохнули? готовы?)
concurrent mark/sweep garbage collection with weak reference support.
https://github.com/spencertipping/bash-lambda