bash 删除bash中每一行的最后一个单词
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/10219438/
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
Delete last word in each line in bash
提问by Michael Rauh
I am trying to go through a file, and delete the last word in each line. Currently, I am using the command
我正在尝试浏览一个文件，并删除每一行中的最后一个单词。目前，我正在使用命令
sed 's/^*\n//' old.txt > new.txt
but it is coming out that old.txt is the same as new.txt. Thanks for any help, and let me know if I can clarify the question. Also, in order to define 'word' I am just using spaces.
但结果是 old.txt 与 new.txt 相同。感谢您的帮助，如果我能澄清问题，请告诉我。另外，为了定义“单词”，我只是使用空格。
回答by David Z.
Try the following. \w*matches the last word inside of the file and $anchors the search to the end of the line.
请尝试以下操作。\w*匹配文件中的最后一个单词$并将搜索定位到行尾。
sed s/'\w*$'// old.txt > new.txt
The reason that old.txt is coming out as new.txt is likely because your regular expression ^*\nis not matching any lines in old.txt.
old.txt 作为 new.txt 出现的原因可能是因为您的正则表达式^*\n与 old.txt 中的任何行都不匹配。
回答by E1Suave
The following is an inline edit. PRIOR TO RUNNING ANYTHING PLEASE BACKUP YOUR FILE.
以下是内联编辑。在运行任何东西之前，请备份您的文件。
sed -i 's/[[:alnum:]]*$//' /yourfile
If you are working on OS X, you may want to try the following
如果您在 OS X 上工作，您可能想尝试以下操作
sed -i '' 's/[[:alnum:]]*$//' /yourfile
If you are not interested in writing directly back to the original file, but would like the output to be printed.
如果您对直接写回原始文件不感兴趣，但希望打印输出。
sed 's/[[:alnum:]]*$//' /yourfile
