查找和替换含SED非转义字符变量 [英] Find and replace variables containing non-escaped characters with sed
问题描述
我可以利用这一点,找到飞的所有实例,并在我的文件虫子替换为:
SED -i'S /飞/昆虫/ G'./animals.txt
我怎样才能找到一个BASH变量,并用另一个变量BASH取代它呢?例如:
名称= $(回声飞)
类别= $(回声虫)
SED -iS / $名称/ $类/ G'./animals.txt
更新:
我使用GNU sed的版本4.2.1。当我尝试以下解决方案,它会报告这个错误:
的sed:-e前pression#1,烧焦73:未知的选项'S'
更新:
我发现为什么错误来了。 $类别
经常含有大量的符号(例如,/,$,@,!,支架,等)。
AME = $(回声飞)
类别= $(回声中/教派)
SED -iS / $名称/ $类/ G./animals.txt
以上code将产生同样的错误:
的sed:-e前pression#1,烧焦7:未知的选项'S'
有没有办法让 SED
完成替换,即使遇到这些符号?
使用双引号
使用双引号,使外壳扩展变量,同时保持空白:
SED -iS / $名称/ $类/ G./animals.txt
注意:如果你需要把反斜线在替换(例如,用于反向引用),则需要双斜杠(\\&安培;包含模式匹配):
使用单引号
如果您已经有很多shell元字符,你可以做这样的事情:
SED -iS /'$模式'/'$类别/ G'./animals.txt
我发现为什么错误来了。 $类经常含有大量的符号(例如,/,$,@,!,支架,等)。
块引用>如果替换或更换部分包含像
/
字符,那么我们就可以使用不同的套SED
分隔符。您可以使用类似 -@%; :| _
等,这不会发生在你的替代和置换发生的任何字符。I can use this, to find all instances of "fly" and replace it with "insect" in my file:
sed -i 's/fly/insect/g' ./animals.txt
How can I find a BASH variable and replace it with another BASH variable? E.g.:
name=$(echo "fly") category=$(echo "insect") sed -i 's/$name/$category/g' ./animals.txt
Update:
I am using GNU sed version 4.2.1. When I try the solutions below, it reports this error:
sed: -e expression #1, char 73: unknown option to `s'
Update:
I discovered why the error is coming up.
$category
frequently contains lots of symbols (e.g. "/", "$", "@", "!", brackets, etc.).ame=$(echo "fly") category=$(echo "in/sect") sed -i "s/$name/$category/g" ./animals.txt
The above code will create the same error:
sed: -e expression #1, char 7: unknown option to `s'
Is there a way to let
sed
complete the replaces, even when it encounters these symbols?解决方案Using double quotes
Use double quotes to make the shell expand variables while keeping whitespace:
sed -i "s/$name/$category/g" ./animals.txt
Note: if you need to put backslashes in your replacement (e.g. for back references), you need double slashes (\& contains the pattern match):
Using single quotes
If you've a lot shell meta-characters, you can do something like this:
sed -i 's/'$pattern'/'$category'/g' ./animals.txt
I discovered why the error is coming up. $category frequently contains lots of symbols (e.g. "/", "$", "@", "!", brackets, etc.).
If the substitution or replacement portion contains characters like
/
then we can use different sets ofsed
delimiters. You can use something like -@ % , ; : | _
etc. any character that does not happen to occur in your substitution and replacement.这篇关于查找和替换含SED非转义字符变量的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!