如何在文本的某一行的末尾附加某些内容

Question

我想在某一行的末尾添加一些东西(有一些给定的字符).例如,文本是:

Line1:  I just want to make clear of the problem
Line2:  Thanks to all who look into my problem
Line3:  How to solve the problem?
Line4:  Thanks to all.

然后我想在最后添加"请帮助我"

Line2:  Thanks to all who look into my problem

这"Line2"是关键词.(也就是说,我必须通过关键词grep这一行来附加一些东西).

所以脚本之后的文本应该是:

Line1:  I just want to make clear of the problem
Line2:  Thanks to all who look into my problem Please help me
Line3:  How to solve the problem?
Line4:  Thanks to all.

我知道sed可以在某些行上附加某些内容但是,如果我使用sed '/Line2/a\Please help me'它,它将在该行之后插入一个新行.那不是我想要的.我希望它附加到当前行.

有人可以帮帮我吗？

非常感谢!

Answer 1

我可能会选择约翰的sed解决方案但是,既然你问过这个问题awk:

$ echo 'Line1:  I just want to make clear of the problem
Line2:  Thanks to all who look into my problem
Line3:  How to solve the problem?
Line4:  Thanks to all.' | awk '/^Line2:/{$0=$0" Please help me"}{print}'

这输出:

Line1:  I just want to make clear of the problem
Line2:  Thanks to all who look into my problem Please help me
Line3:  How to solve the problem?
Line4:  Thanks to all.

关于它如何工作的解释可能会有所帮助.将awk脚本视为左侧的条件和右侧的命令:

/^Line2:/ {$0=$0" Please help me"}
          {print}

awk对处理的每一行执行这两个子句.

如果该行与正则表达式匹配^Line2:(在行的开头表示"Line2:"),则$0通过附加所需的字符串($0整行读入awk)进行更改.

如果该行匹配空条件(所有行将与此匹配),print则执行.这输出当前行$0.

所以你可以看到它只是一个简单的程序,可以根据需要修改行,并输出行,修改与否.

此外,/^Line2:/即使是sed解决方案,您也可能希望将其用作键,这样您就不会Line2在文本中间或Line20通过Line29,Line200通过Line299等接收:

sed '/^Line2:/s/$/ Please help me/'

Answer 2

sed '/Line2/ s/$/ Please help me/'