[:class:] в bash

Никто не подскажет начинающему, как заставить работать конструкцию [:class:] в bash?

В man bash сказано так:
Within [ and ], character classes can be specified using the syntax [:class:], where class is one of the following classes defined in the POSIX.2 standard:
alnum alpha ascii blank cntrl digit graph lower print punct space upper word xdigit
A character class matches any character belonging to that class. The word character class matches letters, digits, and the character _.

Я создал файлы b1n, ..., b9n, но команда echo b[:digit:]* выводит b[:digit:]*, а не список файлов.

shopt выдает следующее:
cdable_vars off
cdspell off
checkhash off
checkwinsize off
cmdhist on
dotglob off
execfail off
expand_aliases on
extdebug off
extglob on
extquote on
failglob off
force_fignore on
gnu_errfmt off
histreedit off
histappend off
histverify off
hostcomplete on
huponexit off
interactive_comments on
lithist off
login_shell off
mailwarn off
no_empty_cmd_completion off
nocaseglob off
nullglob off
progcomp on
promptvars on
restricted_shell off
shift_verbose off
sourcepath on
xpg_echo off