如何删除包含变量的文件中的所有行，仅当位于 BASH 中大括号之间的某处时？
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How to remove all lines in a file containing a variable, only when located on a line somewhere between braces in BASH?
提问by Village
I am trying to remove all of the matches of $wordfrom a file, but only on lines where $wordis placed somewhere within {and }which also appear on the same line, e.g.:
我试图$word从文件中删除所有匹配项，但仅在$word放置在某处{并且}也出现在同一行上的行上，例如：
{The cat liked} the fish.
The mouse {did not like} the cat.
The {cat did not} like the spider.
If $wordis set to "cat", then lines 1 and 3 are deleted, because "cat" appears between the {and }. If $wordis set to "like", then lines 1 and 2 are deleted, because this search term appears on those lines between the {and }. Line 3 is not deleted, because likeappears outside of the braces.
如果$word设置为“cat”，则删除第 1 行和第 3 行，因为“cat”出现在{和之间}。如果$word设置为“like”，则删除第 1 行和第 2 行，因为此搜索词出现在{和之间的那些行上}。第 3 行没有被删除，因为它like出现在大括号之外。
- The braces are never nested.
- The braces never appear split across lines.
- 大括号从不嵌套。
- 大括号永远不会出现跨行拆分。
I have tried various things, but these all returned errors:
我尝试了各种方法，但这些都返回了错误：
sed -i "/\{*$word*\}/d" ./file.txt
sed -i "/\{.*$word.*\}/d" ./file.txt
sed -i "/\{(.*)$word(.*)\}/d" ./file.txt
How can I remove all of the lines in a file containing a variable, but only when the found variable was on a line and found between two braces?
如何删除包含变量的文件中的所有行，但仅当找到的变量在一行上并在两个大括号之间找到时才删除？
回答by cybeliak
sed -i "/{.*$word.*}/d" ./file.txt
\{in sed actually have a special meaning, not the literal {, you should just write a {to represent the literal character. (which would be confusing if you are well familiar with perl regex ...)
\{在 sed 中实际上有一个特殊的含义，而不是字面量{，你应该只写 a{来代表字面量字符。（如果您非常熟悉 perl regex，这会令人困惑...）
Edit:
编辑：
Be careful with -i, if this is in a script, and accidently $wordis not defined or set to empty string, this command will delete alllines containing { no matter what between }.
请注意-i，如果这是在脚本中，并且不小心$word未定义或设置为空字符串，则此命令将删除所有包含{ no matter what between }.
回答by Floris
I would take the answer that @cybeliak gave a little further. If you really want to match catand not, say scat, then you need to delimit your expression with word boundaries:
我会更进一步地接受@cybeliak 给出的答案。如果你真的想匹配cat而不是，比如说scat，那么你需要用单词边界来分隔你的表达式：
sed '/{.*[[:<:]]'$word'[[:>:]].*}/d'
Note - I prefer to use ' 'style quotes to prevent any unintended side-effects...
注意 - 我更喜欢使用' '样式引号来防止任何意外的副作用......
As an aside, I am a big fan of notusing the -iflag. Pipe the result into a different file and confirm for yourself that it's good, before deleting the original.
顺便说一句，我是不使用-i国旗的忠实粉丝。在删除原始文件之前，将结果通过管道传输到另一个文件中并自己确认它是好的。
回答by anubhava
Much easier to do with awk:
使用 awk 更容易：
awk -v s="cat" -F '[{}]' '!( ~ s)' file
The mouse {did not like} the cat.
awk -v s="like" -F '[{}]' '!( ~ s)' file
The {cat did not} like the spider.
回答by potong
This might work for you (GNU sed):
这可能对你有用（GNU sed）：
sed -i '/{[^}]*'"$word"'[^}]*}/d' file
N.B. $wordshould not contain }or /.
NB$word不应包含}或/。
