bash 从括号中提取字符串
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Extract string from brackets
提问by Dang Khoa
I'm pretty new at bash so this is a pretty noob question..
我在 bash 方面很新，所以这是一个非常菜鸟的问题..
Suppose I have a string:
假设我有一个字符串：
string1 [string2] string3 string4
I would like to extract string2from the square brackets; but the brackets may be surrounding any other string at any other time.
我想string2从方括号中提取；但括号可以在任何其他时间包围任何其他字符串。
How would I use sed, etc, to do this? Thanks!
我将如何使用sed等来做到这一点？谢谢！
回答by jman
Try this:
尝试这个：
echo $str | cut -d "[" -f2 | cut -d "]" -f1
回答by Daniel Haley
Here's one way using awk:
这是使用 awk 的一种方法：
echo "string1 [string2] string3 string4" | awk -F'[][]' '{print }'
This sed option also works:
这个 sed 选项也有效：
echo "string1 [string2] string3 string4" | sed 's/.*\[\([^]]*\)\].*//g'
Here's a breakdown of the sed command:
这是 sed 命令的细分：
s/ <-- this means it should perform a substitution
.* <-- this means match zero or more characters
\[ <-- this means match a literal [ character
\( <-- this starts saving the pattern for later use
[^]]* <-- this means match any character that is not a [ character
the outer [ and ] signify that this is a character class
having the ^ character as the first character in the class means "not"
\) <-- this closes the saving of the pattern match for later use
\] <-- this means match a literal ] character
.* <-- this means match zero or more characters
/ <-- this means replace everything matched with the first saved pattern
(the match between "\(" and "\)" )
/g <-- this means the substitution is global (all occurrences on the line)
回答by Alex Howansky
In pure bash:
在纯 bash 中：
STR="string1 [string2] string3 string4"
STR=${STR#*[}
STR=${STR%]*}
echo $STR
回答by ghostdog74
Here's another one , but it takes care of multiple occurrences, eg
这是另一个，但它处理多次出现，例如
$ echo "string1 [string2] string3 [string4 string5]" | awk -vRS="]" -vFS="[" '{print }'
string2
string4 string5
The simple logic is this, you split on "]" and go through the split words finding a "[", then split on "[" to get the first field. In Python
简单的逻辑是这样的，您在“]”上拆分并通过拆分词找到“[”，然后在“[”上拆分以获得第一个字段。在 Python 中
for item in "string1 [string2] string3 [string4 string5]".split("]"):
if "[" in item:
print item.split("]")[-1]
回答by outdev
Specify awk multiple delimiters with -F '[delimiters]'
使用-F '[delimiters]'指定 awk 多个分隔符
If the delimiters are square brackets, put them back to back like this ][
如果分隔符是方括号，请将它们像这样背靠背][
awk -F '[][]' '{print }'
otherwise you will have to escape them
否则你将不得不逃离他们
awk -F '[\[\]]' '{print }'
Other examples to get the value between the brackets:
获取括号之间值的其他示例：
echo "string1 (string2) string3" | awk -F '[()]' '{print }'
echo "string1 {string2} string3" | awk -F '[{}]' '{print }'
回答by dawg
Another awk:
另一个awk：
$ echo "string1 [string2] string3 [string4]" |
awk -v RS=[ -v FS=] 'NR>1{print }'
string2
string4
回答by Robert Sutton
Here is an awk example, but I'm matching on parenthesis which also makes it more obvious of how the -F works.
这是一个 awk 示例，但我在括号上进行匹配，这也使 -F 的工作原理更加明显。
echo 'test (lskdjf)' | awk -F'[()]' '{print $2}'
回声'测试（lskdjf）' | awk -F'[()]' '{print $2}'
回答by Luca Davanzo
Inlinesolution could be:
内联解决方案可能是：
a="first \"Foo1\" and second \"Foo2\""
echo ${a#*\"} | { read b; echo ${b%%\"*}; }
You can test in single line:
您可以单行测试：
a="first \"Foo1\" and second \"Foo2\""; echo ${a#*\"} | { read b; echo ${b%%\"*}; }
Output: Foo1
输出：Foo1
Example with brackets:
带括号的示例：
a="first [Foo1] and second [Foo2]"
echo ${a#*[} | { read b; echo ${b%%]*}; }
That in one line:
在一行中：
a="first [Foo1] and second [Foo2]"; echo ${a#*[} | { read b; echo ${b%%]*}; }
Output: Foo1
输出：Foo1
回答by Sudhir Sinha
Read file in which the delimiter is square brackets:
$ cat file
123;abc[202];124
125;abc[203];124
127;abc[204];124
To print the value present within the brackets:
$ awk -F '[][]' '{print }' file
202
203
204
At the first sight, the delimiter used in the above command might be confusing. Its simple. 2 delimiters are to be used in this case: One is [ and the other is ]. Since the delimiters itself is square brackets which is to be placed within the square brackets, it looks tricky at the first instance.
乍一看，上述命令中使用的分隔符可能令人困惑。这很简单。在这种情况下将使用 2 个分隔符：一个是 [，另一个是 ]。由于定界符本身是方括号，方括号要放在方括号内，因此一开始看起来很棘手。
Note: If square brackets are delimiters, it should be put in this way only, meaning first ] followed by [. Using the delimiter like -F '[[]]' will give a different interpretation altogether.
注意：如果方括号是分隔符，则只能这样放置，意思是先是 ] 后是 [。使用像 -F '[[]]' 这样的分隔符将给出完全不同的解释。
Refer this link: http://www.theunixschool.com/2012/07/awk-10-examples-to-read-files-with.html
请参阅此链接：http: //www.theunixschool.com/2012/07/awk-10-examples-to-read-files-with.html
