在 sed -i (regex?) bash 中使用变量
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/19252880/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Using variable inside of sed -i (regex?) bash
提问by Joel Damata
I've looked at the other sedpages here and i cannot find one that uses -iwith a variable in the regex search portion. I am trying to cut out a requested line in the file myresolv.confand by getting its line number. 5 people in my class are all stuck :(
Any help is awesome
我查看了sed此处的其他页面-i，但在正则表达式搜索部分找不到与变量一起使用的页面。我试图在文件中删除请求的行myresolv.conf并获取其行号。我班上的 5 个人都被卡住了 :( 任何帮助都很棒
line=$(grep -n "" ./myresolv.conf | cut -d: -f1)
sed -i "$line" ./myresolv.conf
回答by jkshah
I assume, you mean remove linewhen you say cut out line.
我想，你的意思是remove line当你说cut out line.
Try using grepwith -voption. I believe you don't need sedhere.
尝试使用grepwith-v选项。我相信你不需要sed这里。
grep -v "" ./myresolv.conf
Or if you want to delete line in the file itself
或者，如果您想删除文件本身中的行
sed -i.bak "//d" ./myresolv.conf
It's good to use -iwith .bakto create backup file before overwirting changes.
在覆盖更改之前使用-iwith.bak创建备份文件很好。
回答by twalberg
It would seem you want to delete a specific line from a file. You're hopefully getting a single line number in your linevariable (but beware - if you have multiple lines that match, you're going to get a list of numbers, and that will cause the rest of your process to explode). The problem you have is that the command you are feeding sedis simply the line number - you are not specifying anything for sedto do with that line number. So, perhaps you want this:
您似乎想从文件中删除特定行。您希望在您的line变量中获得一个单一的行号（但要注意 - 如果您有多个匹配的行，您将获得一个数字列表，这将导致您的其余过程爆炸）。您遇到的问题是您提供的命令sed只是行号 - 您没有指定sed与该行号有关的任何内容。所以，也许你想要这个：
sed -i "${line}d" file.txt
If I've misunderstood your question, and you're not wanting to delete that line, but simply print it, then replace the dwith p...
如果我误解了你的问题，而你不想删除该线，但只是打印出来，然后更换d与p...
