Shell 如何在两个相同的标记模式之间获取特定数据

使用awk或sed，如何选择发生在两个相同标记模式之间的线？可能有多个标有这些图案的部分

例如：假设文件包含：

$$$
lines between dollar and AT
@@@
lines between first and second AT
@@@
lines between second and third AT
@@@
lines between third and fourth AT
@@@

使用

我得到的内容介于$$$和第一次出现的@@@之间

我的疑问是，如何在第一次和第三次出现@@@

预期产出为：

lines between first and second AT
@@@
lines between second and third AT

---

awk

似乎是这项工作的更明智的工具，这主要是因为它允许您在命令行上比sed更容易地指定参数（也就是说，它可以理智地处理数字）

我会用

awk -v pattern='^@@@$' -v first=1 -v last=3 '$0 ~ pattern { ++count; if(count == first) next } count == last { exit } count >= first' 2.txt

这项工作如下：

$0 ~ pattern {              # When the delimiter pattern is found:
  ++count                   # increase counter.
  if(count == first) {      # If we found the starting pattern
    next                    # skip to next line. This handles the fencepost.
  }
}
count == last {             # If we found the end pattern, stop processing.
  exit
}
count >= first              # Otherwise, if the line comes after the starting
                            # pattern, print the line.

---

添加一个计数器，检查计数器，如果计数器=值，则打印数据作为开始：

awk'/@@@cnt+=1}cnt；cnt==3{exit}input.txt

可能还会在Fredrik Pihl注释中添加以下内容，即删去第一行和最后一行<代码>awk'/@@@cnt+=1}cnt；cnt==3{exit}'sed_sample.txt|sed-e'1,1d'-e'$d'。

$0 ~ pattern {              # When the delimiter pattern is found:
  ++count                   # increase counter.
  if(count == first) {      # If we found the starting pattern
    next                    # skip to next line. This handles the fencepost.
  }
}
count == last {             # If we found the end pattern, stop processing.
  exit
}
count >= first              # Otherwise, if the line comes after the starting
                            # pattern, print the line.