Merging Text Files Side-by-Side in Linux Bash Using pr Command

Introduction

In the vast toolbox of Linux command-line utilities, pr stands out when you need to process text for printing or viewing in formatted ways. While typically used for preparing data for printing, it can be repurposed for various other tasks, such as merging multiple text files side-by-side. In this blog, we'll explore how to use the pr command specifically with the -m and -t options to merge files side by side without headers, offering both an easy guide and practical examples.

Q&A: Merging Files with pr -m -t

Q1: What does the pr command do in Linux?

A1: The pr command in Linux is used to convert text files for printing. It can format plain text in a variety of ways, such as pagination, columnar formatting, and header/footer handling.

Q2: How do you use pr to merge files side-by-side?

A2: By using the -m and -t options in pr, you can merge files horizontally without the usual headers. The -m option stands for 'merge', which combines multiple files horizontally, and the -t option suppresses headers and footers that would normally be added by pr.

Q3: Can I merge more than two files using pr -m -t?

A3: Absolutely! pr -m -t is not limited to just two files. You can specify multiple files as input, and it will merge them side-by-side according to the order they are listed in the command.

Background: Using pr for Merging Files

The pr command's primary role is formatting text for printing, but its versatility makes it useful for other tasks. Simple examples of how pr can be utilized besides file merging include:

• Pagination: pr can divide long text into manageable, numbered pages.

• Column Creation: It can format a single file into multiple columns.

To focus back on merging, here's a quick breakdown of the command structure for merging two simple text files named file1.txt and file2.txt:

pr -m -t file1.txt file2.txt

This command line will output the contents of file1.txt and file2.txt side-by-side to the terminal. Each line from file1.txt is paired horizontally with the corresponding line from file2.txt.

Executable Script: Demonstrating File Merging

Let’s consider we have two text files, left.txt and right.txt. Here's a simple bash script to demonstrate merging them side-by-side using pr -m -t.

#!/bin/bash

# Create two sample text files.
echo -e "Alice\nBob\nCharlie" > left.txt
echo -e "Manager\nEngineer\nDesigner" > right.txt

# Use pr to merge the files side-by-side
pr -m -t left.txt right.txt

# Clean up by removing text files
rm left.txt right.txt

This script first creates two files with sample content, then merges them side by side using the pr command, and finally cleans up by deleting the files.

Summary and Conclusion

The pr command, while traditionally used for printing preparation, offers great versatility for various text-processing tasks, including file merging. By using the -m and -t options, you can easily merge multiple files side-by-side without any headers, making it extremely useful for preparing reports, summaries, or simply formatting output in a more readable side-by-side manner.

Whether you are a system administrator, a programmer, or just a Linux enthusiast, knowing how to leverage such commands can simplify many of your text processing needs and enhance your command-line proficiency.

Further Reading

Here are some further reading examples related to the usage of Linux command-line tools for text processing and file manipulation:

1. GNU 'pr' command overview - This link provides comprehensive documentation on the pr command used in GNU/Linux for text formatting: GNU Coreutils - pr

2. Advanced Bash-Scripting Guide: Focuses extensively on script writing and handling text in Linux, including use of the pr command: Advanced Bash-Scripting Guide

3. Linux Command Line Text Manipulation Handbook: This book or online resource can help you explore other text manipulation commands on the Linux command line: Linux Text Manipulation

4. Using 'awk' and 'sed' for text processing: Delve deeper into text processing with these powerful tools: Awk and Sed

5. Unix & Linux Stack Exchange: A Q&A site with real-world problems and solutions involving pr and other Unix/Linux commands: Unix & Linux Stack Exchange - pr command

These resources will expand your understanding and skill set related to text file manipulation and general command-line proficiency in Linux environments.