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Converting Text Files to CSV Using Command Line: A How-To Guide

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In this guide, we will explore how to convert text files into CSV format using command-line tools. This is a valuable skill for system administrators and developers who often need to process and analyze data stored in text files.

Quick Answer

Converting text files to CSV using the command line can be done using tools like jq or programming languages like Python. These methods allow you to parse and transform the data into CSV format, making it easier to work with for data analysis tasks. Additionally, online converters provide a web-based solution for converting text files to CSV format.

What is a CSV File?

CSV stands for Comma Separated Values. It is a simple file format used to store tabular data, such as a spreadsheet or database. Each line in the CSV file corresponds to a row in the table, and each field (column) in the table is separated by a comma.

Why Convert Text Files to CSV?

Text files are a common format for data storage, but they can be difficult to work with for complex data analysis. On the other hand, CSV files are widely supported by data analysis tools and libraries, making them a more convenient choice for data manipulation tasks.

Method 1: Using jq Command-Line Tool

The jq tool is a powerful command-line JSON processor. It can parse and transform JSON-like data into other formats, including CSV.

Here’s a sample command:

jq -r 'keys_unsorted as $keys | $keys, map([.[ $keys[] ]])[] | @csv' input.txt > output.csv

Let’s break down this command:

  • jq -r: Runs jq in raw output mode, which means the output will be plain text instead of JSON-encoded.
  • keys_unsorted as $keys: Extracts the keys from the first object in the input and assigns them to the variable $keys.
  • $keys, map([.[ $keys[] ]])[]: Creates an array for each object, with the values corresponding to the keys in $keys.
  • @csv: Formats the arrays as CSV.
  • input.txt > output.csv: Reads from input.txt and writes the result to output.csv.

Note: You can install jq from the official website.

Method 2: Using Python

Python is a versatile language with built-in support for CSV file manipulation. Here’s a Python script that reads a text file and writes it to a CSV file:

import json
import csv

with open('input.txt', 'r') as file:
 data = [json.loads(line) for line in file]

keys = data[0].keys()
with open('output.csv', 'w', newline='') as file:
 writer = csv.DictWriter(file, fieldnames=keys)

This script works as follows:

  • It reads the text file line by line, parses each line as JSON, and stores the parsed data in a list.
  • It extracts the keys from the first object to use as column names in the CSV file.
  • It writes the data to a CSV file using the csv.DictWriter class.

Note: You can download Python from the official website.

Method 3: Using Online Converters

If you prefer a web-based solution, you can use online converters like Convert JSON to CSV or JSON to CSV Converter. These tools allow you to upload your file and convert it to CSV format directly in your browser.


Converting text files to CSV format can be done in various ways, depending on your preference and the tools available to you. Whether you choose to use a command-line tool like jq, a programming language like Python, or an online converter, the result will be a CSV file that’s easier to work with for data analysis tasks.

How do I install `jq` on my system?

To install jq, you can visit the official website at and follow the installation instructions provided for your specific operating system.

Can I convert text files with different formats to CSV using `jq`?

Yes, jq can handle various text file formats as long as they can be parsed as JSON-like data. You may need to adjust the command accordingly to extract the desired fields for conversion to CSV.

Do I need to have Python installed to use Method 2?

Yes, you need to have Python installed on your system to execute the Python script. You can download Python from the official website at and follow the installation instructions for your operating system.

Can I convert large text files to CSV using Method 2?

Yes, Method 2 can handle large text files. The script reads the text file line by line, so it doesn’t load the entire file into memory at once, making it suitable for processing large files.

Are online converters safe to use?

While most online converters are safe to use, it is always recommended to exercise caution when uploading your files to third-party websites. Ensure that you use reputable and trusted online converters to protect your data and privacy.

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