bash 使用sed从字符串中删除子字符串
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Removing substring out of string using sed
提问by rluks
I am trying to remove substring out of variable using sed like this:
我正在尝试使用 sed 从变量中删除子字符串，如下所示：
PRINT_THIS="`echo "$fullpath" | sed 's/${rootpath}//' -`"
where
在哪里
fullpath="/media/some path/dir/helloworld/src"
rootpath=/media/some path/dir
I want to echo just rest of the fullpath like this (i am using this on whole bunch of directories, so I need to store it in variables and do it automatically
我想像这样回显完整路径的其余部分（我在整个目录上使用它，所以我需要将它存储在变量中并自动执行
echo "helloworld/src"
using variable it would be
使用变量它会是
echo "Directory: $PRINT_THIS"
Problem is, I can not get sed to remove the substring, what I am I doing wrong? Thanks
问题是，我无法通过 sed 删除子字符串，我做错了什么？谢谢
回答by Mat
You don't need sedfor that, bashalone is enough:
你不需要这样做sed，bash一个人就足够了：
$ fullpath="/media/some path/dir/helloworld/src"
$ rootpath="/media/some path/dir"
$ echo ${fullpath#${rootpath}}
/helloworld/src
$ echo ${fullpath#${rootpath}/}
helloworld/src
$ rootpath=unrelated
$ echo ${fullpath#${rootpath}/}
/media/some path/dir/helloworld/src
Check out the String manipulationdocumentation.
查看字符串操作文档。
回答by Gilles Quenot
To use variables in sed, you must use it like this :
要在 sed 中使用变量，您必须像这样使用它：
sed "s@$variable@@g" FILE
two things :
两件事情 ：
- I use double quotes (shell don't expand variables in single quotes)
- I use another separator that doesn't conflict with the slashes in your paths
- 我使用双引号（shell 不扩展单引号中的变量）
- 我使用另一个与路径中的斜杠不冲突的分隔符
Ex:
前任：
$ rootpath="/media/some path/dir"
$ fullpath="/media/some path/dir/helloworld/src"
$ echo "$fullpath"
/media/some path/dir/helloworld/src
$ echo "$fullpath" | sed "s@$rootpath@@"
/helloworld/src
