bash 如何在case语句中使用模式？
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How to use patterns in a case statement?
提问by Ramiro Rela
The manpage says that casestatements use "filename expansion pattern matching".
I usually want to have short names for some parameters, so I go:
该man页面说case语句使用“文件名扩展模式匹配”。
我通常想要一些参数的短名称，所以我去：
case in
req|reqs|requirements) TASK="Functional Requirements";;
met|meet|meetings) TASK="Meetings with the client";;
esac
logTimeSpentIn "$TASK"
I tried patterns like req*or me{e,}twhich I understand would expand correctly to match those values in the context of filename expansion, but it doesn't work.
我尝试了类似req*或me{e,}t我理解的模式可以正确扩展以匹配文件名扩展上下文中的这些值，但它不起作用。
回答by Paused until further notice.
Brace expansion doesn't work, but *, ?and []do. If you set shopt -s extglobthen you can also use extended pattern matching:
大括号扩展不起作用，但是*,?和[]做。如果设置，shopt -s extglob则还可以使用扩展模式匹配：
?()- zero or one occurrences of pattern*()- zero or more occurrences of pattern+()- one or more occurrences of pattern@()- one occurrence of pattern!()- anything except the pattern
?()- 模式出现零次或一次*()- 零次或多次出现的模式+()- 出现一次或多次模式@()- 出现一次模式!()- 除了图案之外的任何东西
Here's an example:
下面是一个例子：
shopt -s extglob
for arg in apple be cd meet o mississippi
do
# call functions based on arguments
case "$arg" in
a* ) foo;; # matches anything starting with "a"
b? ) bar;; # matches any two-character string starting with "b"
c[de] ) baz;; # matches "cd" or "ce"
me?(e)t ) qux;; # matches "met" or "meet"
@(a|e|i|o|u) ) fuzz;; # matches one vowel
m+(iss)?(ippi) ) fizz;; # matches "miss" or "mississippi" or others
* ) bazinga;; # catchall, matches anything not matched above
esac
done
回答by plundra
I don't think you can use braces.
我不认为你可以使用大括号。
According to the Bash manual about case in Conditional Constructs.
根据 Bash 手册关于Conditional Constructs 中的case 。
Each patternundergoes tilde expansion, parameter expansion, command substitution, and arithmetic expansion.
每个模式都经历波浪号扩展、参数扩展、命令替换和算术扩展。
Nothing about Brace Expansionunfortunately.
不幸的是，没有关于支撑扩展的内容。
So you'd have to do something like this:
所以你必须做这样的事情：
case in
req*)
...
;;
met*|meet*)
...
;;
*)
# You should have a default one too.
esac
