It implements in the main core
* new brace expansion {a..b} --- integer/letter generation, positional parameters and array expansion
* new parameter expansion ${var|...} --- content filtering, list comprehension (like Python)
* new command substitution $(=...) --- floating-point hook to Awk
* extended case statement --- regex, continuation, then/else sections
* extended for/while/until loops --- then/else sections, multiple for-loop variables
* try-block with integer exception (like Python)
* new <<+ here-document --- relative indentation
and as dynamically loadable builtins
* extended read/echo builtins --- DOS lines
* sscanf(3), <string.h> and <ctype.h> wrappers, ASCII/string conversion
* new raise builtin for try-block
* array cut/splicing, array filter/map/zip/unzip (like Python)
* regex(3) operations --- match, split, search, replace, callback
* HTML template engine (like PHP, JSP, ASP)
* GDBM, SQLite, PostgreSQL, and MySQL database interface
* Expat XML parser interface
* stack/queue operations on arrays and positional parameters
* x-y character plot
Вот такой забавный зверек. Надо будет глянуть подробнее.
http://home.eol.ca/~parkw/index.html#bash
Особо интересует мнение alv'a.
