查找前后替换字符串

Question

我一直在尝试进行 sed 替换。出于某种原因，我无法理解 sed 和正则表达式（这是我的第二个 sed 问题）

基本上我想查找文本并替换，然后找到下一次出现的某些文本并替换它

到目前为止我有这个

echo "This could be anywhere and this bit should be changed \$\{hcvar-BookName\} and this would remain" | sed 's/$\\{hcvar-/" + hcvar-/g'

这会返回：

*This could be anywhere and this bit should be changed " + hcvar-BookName\} and this would remain*

但是我想返回

*This could be anywhere and this bit should be changed " + hcvar-BookName + " and this would remain*

这会将 } 替换为 + "

逻辑是这样的：

Find: \$\{hcvar-
Replace with:  " + hcvar-
Then find the next occurrence of: \}
Replace with: + "

要替换的第二位将紧跟在包含以下内容的字符串之后：hcvar-

这应该适用于以下字符串示例

• 这可能在任何地方，应该更改此位 \${hcvar-BookName} 这将保留
• 这可能在任何地方，并且 应该更改此位 \${hcvar-somethingelse} 这将 留下
• 这可能在任何地方，应该更改此位
  \${hcvar-wouldnevercontainspaces} 这将保留

任何帮助将不胜感激。

Answer 1

假设您的输入实际上是：

... changed ${hcvar-BookName} and ...

然后以下将起作用：

$ sed 's/${\([^}]*\)}/" + \1 + "/' file.txt
This could be anywhere and this bit should be changed " + hcvar-BookName + " and this would remain

注意使用单引号来保留shell的特殊字符：

$ echo '...changed ${hcvar-BookName} and ...' | sed '...' 

如果输入确实使用\{，即：... $\{hello\} ...，那么这可能有效：

$ sed 's/$\\{\([^}]*\)\\}/" + \1 + "/' file.txt
This could be anywhere and this bit should be changed " + hcvar-BookName + " and this would remain

细分：

s/            /          / # Replace ... with ...
  ${         }             # Literal ${ and literal }
    \(     \)              # \( and \) is a capturing group
      [^}]*                # Match everything but } zero or more times
               " + \1 + "  # \1 will be expanded to the captured result
                           # from \(, \). The rest is literal

如果您需要在每行上进行多次替换，请添加 global：

s/pattern/replacement/g
#                     ^ Global flag

Answer 2

你需要用反斜杠转义 $：

echo "This could be anywhere and this bit should be changed \$\{hcvar-BookName\} and this would remain" | sed -e 's/\$\\{hcvar-/" + hcvar-/g' -e 's/\\}/ +/'

输出：

This could be anywhere and this bit should be changed " + hcvar-BookName + and this would remain