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[#]: collector: (lujun9972)
[#]: translator: ( pityonline )
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (How To Remove/Delete The Empty Lines In A File In Linux)
[#]: via: (https://www.2daygeek.com/remove-delete-empty-lines-in-a-file-in-linux/)
[#]: author: (Magesh Maruthamuthu https://www.2daygeek.com/author/magesh/)
How To Remove/Delete The Empty Lines In A File In Linux
======
Some times you may wants to remove or delete the empty lines in a file in Linux.
If so, you can use the one of the below method to achieve it.
It can be done in many ways but i have listed simple methods in the article.
You may aware of that grep, awk and sed commands are specialized for textual data manipulation.
Navigate to the following URL, if you would like to read more about these kind of topics. For **[creating a file in specific size in Linux][1]** multiple ways, for **[creating a file in Linux][2]** multiple ways and for **[removing a matching string from a file in Linux][3]**.
These are fall in advanced commands category because these are used in most of the shell script to do required things.
It can be done using the following 5 methods.
* **`sed Command:`** Stream editor for filtering and transforming text.
* **`grep Command:`** Print lines that match patterns.
* **`cat Command:`** It concatenate files and print on the standard output.
* **`tr Command:`** Translate or delete characters.
* **`awk Command:`** The awk utility shall execute programs written in the awk programming language, which is specialized for textual data manipulation.
* **`perl Command:`** Perl is a programming language specially designed for text editing.
To test this, i had already created the file called `2daygeek.txt` with some texts and empty lines. The details are below.
```
$ cat 2daygeek.txt
2daygeek.com is a best Linux blog to learn Linux.
It's FIVE years old blog.
This website is maintained by Magesh M, it's licensed under CC BY-NC 4.0.
He got two GIRL babys.
Her names are Tanisha & Renusha.
```
Now everything is ready and i’m going to test this in multiple ways.
### How To Remove/Delete The Empty Lines In A File In Linux Using sed Command?
Sed is a stream editor. A stream editor is used to perform basic text transformations on an input stream (a file or input from a pipeline).
```
$ sed '/^$/d' 2daygeek.txt
2daygeek.com is a best Linux blog to learn Linux.
It's FIVE years old blog.
This website is maintained by Magesh M, it's licensed under CC BY-NC 4.0.
He got two GIRL babes.
Her names are Tanisha & Renusha.
```
Details are follow:
* **`sed:`** It’s a command
* **`//:`** It holds the searching string.
* **`^:`** Matches start of string.
* **`$:`** Matches end of string.
* **`d:`** Delete the matched string.
* **`2daygeek.txt:`** Source file name.
### How To Remove/Delete The Empty Lines In A File In Linux Using grep Command?
grep searches for PATTERNS in each FILE. PATTERNS is one or patterns separated by newline characters, and grep prints each line that matches a pattern.
```
$ grep . 2daygeek.txt
or
$ grep -Ev "^$" 2daygeek.txt
or
$ grep -v -e '^$' 2daygeek.txt
2daygeek.com is a best Linux blog to learn Linux.
It's FIVE years old blog.
This website is maintained by Magesh M, it's licensed under CC BY-NC 4.0.
He got two GIRL babes.
Her names are Tanisha & Renusha.
```
Details are follow:
* **`grep:`** It’s a command
* **`.:`** Replaces any character.
* **`^:`** matches start of string.
* **`$:`** matches end of string.
* **`E:`** For extended regular expressions pattern matching.
* **`e:`** For regular expressions pattern matching.
* **`v:`** To select non-matching lines from the file.
* **`2daygeek.txt:`** Source file name.
### How To Remove/Delete The Empty Lines In A File In Linux Using awk Command?
The awk utility shall execute programs written in the awk programming language, which is specialized for textual data manipulation. An awk program is a sequence of patterns and corresponding actions.
```
$ awk NF 2daygeek.txt
or
$ awk '!/^$/' 2daygeek.txt
or
$ awk '/./' 2daygeek.txt
2daygeek.com is a best Linux blog to learn Linux.
It's FIVE years old blog.
This website is maintained by Magesh M, it's licensed under CC BY-NC 4.0.
He got two GIRL babes.
Her names are Tanisha & Renusha.
```
Details are follow:
* **`awk:`** It’s a command
* **`//:`** It holds the searching string.
* **`^:`** matches start of string.
* **`$:`** matches end of string.
* **`.:`** Replaces any character.
* **`!:`** Delete the matched string.
* **`2daygeek.txt:`** Source file name.
### How To Delete The Empty Lines In A File In Linux using Combination of cat And tr Command?
cat stands for concatenate. It is very frequently used in Linux to reads data from a file.
cat is one of the most frequently used commands on Unix-like operating systems. It’s offer three functions which is related to text file such as display content of a file, combine multiple files into the single output and create a new file.
Translate, squeeze, and/or delete characters from standard input, writing to standard output.
```
$ cat 2daygeek.txt | tr -s '\n'
2daygeek.com is a best Linux blog to learn Linux.
It's FIVE years old blog.
This website is maintained by Magesh M, it's licensed under CC BY-NC 4.0.
He got two GIRL babes.
Her names are Tanisha & Renusha.
```
Details are follow:
* **`cat:`** It’s a command
* **`tr:`** It’s a command
* **`|:`** Pipe symbol. It pass first command output as a input to another command.
* **`s:`** Replace each sequence of a repeated character that is listed in the last specified SET.
* **`\n:`** To add a new line.
* **`2daygeek.txt:`** Source file name.
### How To Remove/Delete The Empty Lines In A File In Linux Using perl Command?
Perl stands in for “Practical Extraction and Reporting Language”. Perl is a programming language specially designed for text editing. It is now widely used for a variety of purposes including Linux system administration, network programming, web development, etc.
```
$ perl -ne 'print if /\S/' 2daygeek.txt
2daygeek.com is a best Linux blog to learn Linux.
It's FIVE years old blog.
This website is maintained by Magesh M, it's licensed under CC BY-NC 4.0.
He got two GIRL babes.
Her names are Tanisha & Renusha.
```
--------------------------------------------------------------------------------
via: https://www.2daygeek.com/remove-delete-empty-lines-in-a-file-in-linux/
作者：[Magesh Maruthamuthu][a]
选题：[lujun9972][b]
译者：[pityonline](https://github.com/pityonline)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://www.2daygeek.com/author/magesh/
[b]: https://github.com/lujun9972
[1]: https://www.2daygeek.com/create-a-file-in-specific-certain-size-linux/
[2]: https://www.2daygeek.com/linux-command-to-create-a-file/
[3]: https://www.2daygeek.com/empty-a-file-delete-contents-lines-from-a-file-remove-matching-string-from-a-file-remove-empty-blank-lines-from-a-file/

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[#]: collector: (lujun9972)
[#]: translator: ( pityonline )
[#]: reviewer: ( )
[#]: publisher: ( )
[#]: url: ( )
[#]: subject: (How To Remove/Delete The Empty Lines In A File In Linux)
[#]: via: (https://www.2daygeek.com/remove-delete-empty-lines-in-a-file-in-linux/)
[#]: author: (Magesh Maruthamuthu https://www.2daygeek.com/author/magesh/)
在 Linux 中如何删除文件中的空行
======
有时你可能需要在 Linux 中删除某个文件中的空行。
如果是的，你可以使用下面方法中的其中一个。
有很多方法可以做到，但我在这里只是列举一些简单的方法。
你可能已经知道 `grep`，`awk` 和 `sed` 命令是专门用来处理文本数据的工具。
如果你想了解更多关于这些命令的文章，请访问这几个 URL。**[在 Linux 中创建指定大小的文件的几种方法][1]**，**[在 Linux 中创建一个文件的几种方法][2]** 以及 **[在 Linux 中删除一个文件中的匹配的字符串][3]**。
这些属于高级命令，它们可用在大多数 shell 脚本中执行所需的操作。
下列 5 种方法可以做到。
* **`sed:`** 过滤和替换文本的流编辑器。
* **`grep:`** 输出匹配到的行。
* **`cat:`** 合并文件并打印内容到标准输出。
* **`tr:`** 替换或删除字符。
* **`awk:`** awk 工具用于执行 awk 语言编写的程序，专门用于文本处理。
* **`perl:`** Perl 是一种用于处理文本的编程语言。
我创建了一个 `2daygeek.txt` 文件来测试这些命令。下面是文件的内容。
```
$ cat 2daygeek.txt
2daygeek.com is a best Linux blog to learn Linux.
It's FIVE years old blog.
This website is maintained by Magesh M, it's licensed under CC BY-NC 4.0.
He got two GIRL babys.
Her names are Tanisha & Renusha.
```
现在一切就绪，我们准备开始用多种方法来验证。
### 使用 sed 命令
sed 是一个<ruby>流编辑器<rt>stream editor</rt></ruby>。流编辑器是用来编辑输入流（文件或管道）中的文本的。
```
$ sed '/^$/d' 2daygeek.txt
2daygeek.com is a best Linux blog to learn Linux.
It's FIVE years old blog.
This website is maintained by Magesh M, it's licensed under CC BY-NC 4.0.
He got two GIRL babes.
Her names are Tanisha & Renusha.
```
以下是命令展开的细节：
* **`sed:`** 该命令本身。
* **`//:`** 标记匹配范围。
* **`^:`** 匹配字符串开头。
* **`$:`** 匹配字符串结尾。
* **`d:`** 删除匹配的字符串。
* **`2daygeek.txt:`** 源文件名。
### 使用 grep 命令
`grep` 可以通过正则表达式在文件中搜索。该表达式可以是一行或多行空行分割的字符，`grep` 会打印所有匹配的内容。
```
$ grep . 2daygeek.txt
or
$ grep -Ev "^$" 2daygeek.txt
or
$ grep -v -e '^$' 2daygeek.txt
2daygeek.com is a best Linux blog to learn Linux.
It's FIVE years old blog.
This website is maintained by Magesh M, it's licensed under CC BY-NC 4.0.
He got two GIRL babes.
Her names are Tanisha & Renusha.
```
Details are follow:
以下是命令展开的细节：
* **`grep:`** 该命令本身。
* **`.:`** 替换任意字符。
* **`^:`** 匹配字符串开头。
* **`$:`** 匹配字符串结尾。
* **`E:`** 使用扩展正则匹配模式。
* **`e:`** 使用常规正则匹配模式。
* **`v:`** 反向匹配。
* **`2daygeek.txt:`** 源文件名。
### 使用 awk 命令
`awk` 可以执行使用 awk 语言写的脚本，大多是专用于处理文本的。awk 脚本是一系列 awk 命令和正则的组合。
```
$ awk NF 2daygeek.txt
or
$ awk '!/^$/' 2daygeek.txt
or
$ awk '/./' 2daygeek.txt
2daygeek.com is a best Linux blog to learn Linux.
It's FIVE years old blog.
This website is maintained by Magesh M, it's licensed under CC BY-NC 4.0.
He got two GIRL babes.
Her names are Tanisha & Renusha.
```
以下是命令展开的细节：
* **`awk:`** 该命令本身。
* **`//:`** 标记匹配范围。
* **`^:`** 匹配字符串开头。
* **`$:`** 匹配字符串结尾。
* **`.:`** 匹配任意字符。
* **`!:`** 删除匹配的字符串。
* **`2daygeek.txt:`** 源文件名。
### 使用 cat 和 tr 命令 组合
`cat` 是<ruby>串联（拼接）<rt>concatenate</rt></ruby>的简写。经常用于在 Linux 中读取一个文件的内容。
cat 是在类 Unix 系统中使用频率最高的命令之一。它提供了常用的三个处理文本文件的功能：显示文件内容，将多个文件拼接成一个，以及创建一个新文件。
tr 可以将标准输入中的字符转换，压缩或删除，然后重定向到标准输出。
```
$ cat 2daygeek.txt | tr -s '\n'
2daygeek.com is a best Linux blog to learn Linux.
It's FIVE years old blog.
This website is maintained by Magesh M, it's licensed under CC BY-NC 4.0.
He got two GIRL babes.
Her names are Tanisha & Renusha.
```
以下是命令展开的细节：
* **`cat:`** cat 命令本身。
* **`tr:`** tr 命令本身。
* **`|:`** 管道符号。它可以将前面的命令的标准输出作为下一个命令的标准输入。
* **`s:`** 替换标数据集中任意多个重复字符为一个。
* **`\n:`** 添加一个新的换行。
* **`2daygeek.txt:`** 源文件名。
### 使用 perl 命令
Perl 表示<ruby>实用的提取和报告语言<rt>Practical Extraction and Reporting Language</rt></ruby>。Perl 在初期被设计为一个专用于文本处理的编程语言，现在已扩展应用到 Linux 系统管理，网络编程和网站开发等多个领域。
```
$ perl -ne 'print if /\S/' 2daygeek.txt
2daygeek.com is a best Linux blog to learn Linux.
It's FIVE years old blog.
This website is maintained by Magesh M, it's licensed under CC BY-NC 4.0.
He got two GIRL babes.
Her names are Tanisha & Renusha.
```
以下是命令展开的细节：
* **`perl:`** perl 命令。
* **`n:`** 逐行读入数据。
* **`e:`** 执行某个命令。
* **`print:`** 打印信息。
* **`if:`** if 条件分支。
* **`//:`** 标记匹配范围。
* **`\S:`** 匹配任意非空白字符。
* **`2daygeek.txt:`** 源文件名。
--------------------------------------------------------------------------------
via: https://www.2daygeek.com/remove-delete-empty-lines-in-a-file-in-linux/
作者：[Magesh Maruthamuthu][a]
选题：[lujun9972][b]
译者：[pityonline](https://github.com/pityonline)
校对：[校对者ID](https://github.com/校对者ID)
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
[a]: https://www.2daygeek.com/author/magesh/
[b]: https://github.com/lujun9972
[1]: https://www.2daygeek.com/create-a-file-in-specific-certain-size-linux/
[2]: https://www.2daygeek.com/linux-command-to-create-a-file/
[3]: https://www.2daygeek.com/empty-a-file-delete-contents-lines-from-a-file-remove-matching-string-from-a-file-remove-empty-blank-lines-from-a-file/