查找以“+”结尾的行

Question

我无法形成一个grep正则表达式，它只能找到那些以+符号结尾的行。例如：

应匹配 - This is a sample line +

不应匹配 - This is another with + in between或This is another with + in between and ends with +

Answer 1

请使用$表示该行的结尾：

grep '+$' file

实施例

$ cat a
This is a sample line +
This is another with + in between
hello

$ grep '+$' a
This is a sample line +

更新

  

如果我想显示最后只有+的行，该怎么办？即使是   line是这样的这是一行+在bw和最后+。一世   不希望这条线匹配。

然后您可以使用awk：

awk '/\+$/ && split($0, a, "\+")==2' file

解释

• /\+$/匹配以+结尾的行。
• split($0, a, "\+")==2根据+分隔符在字符串中划分字符串。返回值是件数，因此2表示它只包含一个+。

实施例

$ cat a
This is a sample line +
This is another with + in between
Hello + and +
hello

$ awk '/\+$/ && split($0, a, "\+")==2' a
This is a sample line +

Answer 2

指定结尾+应不前面有任何其他+，或作为正则表达式：

grep '^[^+]*+'

在fedorqui's a文件的第二版上测试时的输出：

This is a sample line +