仅在不存在换行符时添加它 [英] Add a newline only if it doesn't exist

问题描述

我只想在文件末尾添加换行符，以防止在文件末尾添加多个换行符.

I want to add a newline at the end of a file only if it doesn't exists, this is to prevent multiple newlines at the end of the file.

我希望使用sed. 这是我当前代码遇到的问题:

I'm hoping to use sed. Here's the issues i'm having with my current code:

sed -i -e '/^$/d;$G' /inputfile

echo file1
name1
name2

echo file2
name3
name4
(newline)

当我在文件上运行代码时

when i run my code on to the files;

echo file1
name1
name2
(newline)

echo file2
name3
name4

如果没有则添加一个换行符，但是如果存在则删除一个...这使我感到困惑.

it adds a newline if it doesnt have but removes if it exists... this puzzles me..

推荐答案

由于如果不存在换行符，它将删除换行符，因此您可以简单地使用:

Since it removes newline if it's not there, you could simply use:

echo "" >> file;  sed -ie '/^$/d;$G' file; sed -ie '/^$/d;$G' file

添加换行符并删除所有内容，然后添加换行符.不是优雅的方式，但肯定可以:)

Adds a newline and removes everything then adds newline. Not the elegant way, but certainly works :)

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