How to replace newline (\n) with space using sed

Imagine you have a big text file with lots of lines, like a list of items in a shopping list or server logs. Each item or log entry is on a new line. But what if you need all these items on one line, separated by spaces instead of new lines? This can be useful for many reasons, like making the data easier to read or process with other tools.

This is where sed comes in handy. Sed is a tool that helps you find and change text in files. In this guide, we’ll show you a simple way to use sed to replace new lines with spaces. For example, if you have a file where each new log entry is on a new line, you can use sed to put all the entries on one line, separated by spaces. This makes the data cleaner and easier to handle.

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By the end of this guide, you’ll see how easy it is to make this change and how sed can help you with similar tasks. Let’s get started!

The Command to Replace Newline with Spaces

Here’s the basic sed command to replace newlines with spaces:

sed ':a;N;$!ba;s/\n/ /g' inputfile > outputfile

Let’s break down what this command does:

• :a – This is a label for a loop.
• N – This command appends the next line of input into the pattern space.
• $!ba – This means, if it’s not the last line ($!), branch (b) to the label a.
• s/\n/ /g – This command substitutes (s) every newline character (\n) with a space ( ), globally (g).

Step-by-Step Practical Example

Let’s walk through a real example. Suppose you have a file named logs.txt that looks like this:

Error: Disk full
Warning: High memory usage
Info: System rebooted

To transform this file so that all the entries are on one line, separated by spaces, follow these steps:

1. Open your terminal.
2. Run the sed command:

   
   sed ':a;N;$!ba;s/\n/ /g' logs.txt > single_line_logs.txt
   
   

3. Check the output file:

   Open single_line_logs.txt and you should see:

   
   Error: Disk full Warning: High memory usage Info: System rebooted
   
   

Conclusion

With just a simple sed command, you can transform multiline text files into single-line formats, making data easier to read and process. This is particularly useful for logs and other structured text data. By mastering basic sed commands like this, you can handle a wide variety of text manipulation tasks efficiently. Keep exploring the possibilities of sed to make your text processing tasks easier and more powerful.