Bash语言不支持正则表达式，而是通配的使用方式。sed awk 等工具支持正则表达式。
Bash itself cannot recognize Regular Expressions. Inside scripts, it is commands and utilities – such as sed and awk – that interpret RE’s.
Bash does carry out filename expansion [1] – a process known as globbing – but this does not use the standard RE set. Instead, globbing recognizes and expands wild cards.
Question mark – (?)
一对一通配。
Asterisk – (*)
0或者多个
Caret – (^)
[]: outside: select
[]: inside: highlight
Exclamatory Sign – (!)
outside caret
Dollar Sign – ($)
end
Curly bracket – ({})
多个globbing