Bash case 语句
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Bash case statement
提问by bsmoo
I'm trying to learn case as I was to write a fully functional script.
我正在尝试学习案例，因为我要编写一个功能齐全的脚本。
I'm starting off with the below
我从下面开始
#!/bin/sh
case $@ in
-h|--help)
echo "You have selected Help"
;;
-B|-b)
echo "You have selected B"
;;
-C|-c)
echo "You have selected C"
;;
*)
echo "Valid Choices are A,B,C"
exit 1
;;
esac
I want to use two of these options:
我想使用其中两个选项：
./getopts.sh -h -c
But i get this result Valid Choices are A,B,C
但我得到了这个结果有效的选择是 A、B、C
Please can you help out and let me know what I'm doing wrong?
请你能帮忙告诉我我做错了什么吗？
I want to build a script that will do something if you enter one option but do multiple things if you enter multiple.
我想构建一个脚本，如果您输入一个选项，该脚本将执行某些操作，但如果您输入多个选项，则该脚本将执行多项操作。
Also how would i parse $1 to this script as surley which ever option i enter first (-h) will be $1 ??
另外我将如何将 $1 解析为这个脚本作为 surley 我首先输入的选项（-h）将是 $1 ？
Thanks!
谢谢！
回答by Bruce Barnett
Try this
尝试这个
#!/bin/sh
usage() {
echo `basename for arg in "$@"; do
case $arg in
....
esac
done
`: ERROR: $* 1>&2
echo usage: `basename ##代码##` '[-a] [-b] [-c]
[file ...]' 1>&2
exit 1
}
while :
do
case "" in
-a|-A) echo you picked A;;
-b|-B) echo you picked B;;
-c|-C) echo you picked C;;
-*) usage "bad argument ";;
*) break;;
esac
shift
done
回答by chepner
Using getoptor getoptsis the better solution. But to answer your immediate question, $@is allof your arguments, so -h -c, which doesn't match any of the single-argument patterns in your case statement. You would still need to iterate over your arguments like so
使用getoptorgetopts是更好的解决方案。但是要回答您的直接问题，$@是您的所有参数，所以-h -c，与您的 case 语句中的任何单参数模式都不匹配。你仍然需要像这样迭代你的论点
回答by nitin
to parse the positional arguments like ... $1 , just use $1 in the case stmt and then at the end ... use shift to pust the 2nd arg to $1 and likewise .
要解析像... $1 这样的位置参数，只需在案例 stmt 中使用 $1 ，然后在最后...使用 shift 将第二个 arg 推到 $1 ，同样如此。
also i would put the case stmt in a while loop or better a fxn so that i can run it twice for the two options or the number of options ..........
此外，我会将案例 stmt 放入 while 循环或更好的 fxn 中，以便我可以针对两个选项或选项数量运行它两次.......
$# will let you know how many options/arguments were there .
$# 会让你知道有多少选项/参数。
