Bash：如何拆分字符串并分配多个变量
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Bash: How to split a string and assign multiple variables
提问by kuruvi
I have to split a URL string and assign variables to few of the splits. Here is the string
我必须拆分 URL 字符串并将变量分配给少数拆分。这是字符串
http://web.com/sub1/sub2/sub3/sub4/sub5/sub6
I want to assign variables like below from bash
我想从 bash 分配如下变量
var1=sub2
var2=sub4
var3=sub5
How to do this in bash?
如何在 bash 中做到这一点？
回答by Cyrus
x="http://web.com/sub1/sub2/sub3/sub4/sub5/sub6"
IFS="/" read -r foo foo foo foo var1 foo var2 var3 foo <<< "$x"
echo "$var1 $var2 $var3"
Output:
输出：
sub2 sub4 sub5
Or with an array:
或者使用数组：
x="http://web.com/sub1/sub2/sub3/sub4/sub5/sub6"
IFS="/" read -r -a var <<< "$x"
echo "${var[4]}"
declare -p var
Output:
输出：
sub2 declare -a var='([0]="http:" [1]="" [2]="web.com" [3]="sub1" [4]="sub2" [5]="sub3" [6]="sub4" [7]="sub5" [8]="sub6")'
From man bash:
来自man bash：
IFS: The Internal Field Separator that is used for word splitting after expansion and to split lines into words with the read builtin command.
IFS：内部字段分隔符，用于扩展后的分词，并使用 read 内置命令将行拆分为单词。
回答by Peter Cordes
This should work:
这应该有效：
IFS=/ read -r proto host dummy var1 dummy var2 var3 dummy <<< "$url"
Or read -rato read into an array. read -rmakes backslash non-special.
或者read -ra读入一个数组。 read -r使反斜杠非特殊。
This won't work in bash:
这在 bash 中不起作用：
echo "$url" | read ...
because readwould run in a subshell, so the variables wouldn't be set in the parent shell.
因为read会在子 shell 中运行，所以不会在父 shell 中设置变量。
回答by Thejaswi
I think a better solution would be to assign the result of splitting into an array. For example:
我认为更好的解决方案是将拆分的结果分配到数组中。例如：
IFS='/' read -a array <<< "http://web.com/sub1/sub2/sub3/sub4/sub5/sub6"
Unfortunately, this will create 3 'extraneous' elements, which you will have to take care of!
不幸的是，这将创建 3 个“无关”元素，您必须处理这些元素！
echo ${array[*]}
http: web.com sub1 sub2 sub3 sub4 sub5 sub6
EDIT: In here ${array[1]} is an empty element!
编辑：在这里 ${array[1]} 是一个空元素！
