Alcune delle nuove funzionalità disponibili con la bash versione 4:
w. There is a new shell option: `globstar’. When enabled, the globbing code
treats `**’ specially — it matches all directories (and files within
them, when appropriate) recursively.
cc. There is a new &>> redirection operator, which appends the standard output
and standard error to the named file.
dd. The parser now understands `|&’ as a synonym for `2>&1 |’, which redirects
the standard error for a command through a pipe.
ee. The new `;&’ case statement action list terminator causes execution to
continue with the action associated with the next pattern in the
statement rather than terminating the command.
ff. The new `;;&’ case statement action list terminator causes the shell to
test the next set of patterns after completing execution of the current
action, rather than terminating the command.