How to Count Lines in File Linux [8 Simple Methods]

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Last updated: June 13, 2024

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To count lines in file Linux, you can try these methods:

Command Line Method: wc Command

  1. Open the command prompt.
  2. Navigate to the directory with your file using cd path/to/directory.
  3. Run the command wc -l filename, replacing filename with your file’s name.
  4. The tool will display the line count.

GUI Methods: Sublime Text Editor

  1. Right-click on the file you want to open.
  2. Select Open with other applications and choose Sublime Text.
  3. Open the file in Sublime Text.
  4. Navigate to the bottom of the file to view the total number of lines.

Read the guide below to learn different methods to count lines in file Linux, common errors that can occur during the process and benefits of counting the number of lines in a file.

Have you ever needed to count the number of lines in a file but weren’t sure where to start? Whether you’re handling a small text file or a massive data log, I’m here to help. In this post, I’ll guide you through various tools and techniques, from command-line utilities like wc and awk to text editors, programming languages, and online tools. You’ll get step-by-step instructions for each method, tips for handling large files efficiently, and solutions for common errors. By the end, you’ll know exactly how to count lines in any file quickly and accurately.

How to Count Lines in File Linux

To count lines in file Linux, you can use several methods depending on your tools and preferences. For a quick and easy command-line solution, use wc -l filename to get the line count. Alternatively, you can use awk 'END {print NR}' filename or sed -n '$=' filename for similar results. If you prefer scripting, a simple Python script can read and count lines efficiently. Text editors like Sublime Text also provide built-in line counting features. Choose the method that best fits your workflow and file size.

Here is the detailed step-by-step guide for 8 different methods to count lines in file Linux:

1. wc Command

Command-line tools like wc command provide a quick and automated way to count lines in a file. They are known for their speed and suitability for large-scale line-counting tasks. Command-line tools offer a straightforward and efficient approach to line counting, especially when dealing with large datasets.To Linux line count using wc, follow these easy steps:

  1. Open the command prompt on your computer.
opening terminal 3
  1. Navigate to the directory where the file is located by using the cd command followed by the path to the directory.
navigating to directory 2
  1. Once you are in the desired directory, execute the following command: 
wc -l filename

Replace filename with the actual name of the file you want to count lines for.

  1. The tool will display the line count along with other information, such as the number of words and characters in the file.
viewing number of lines using command line

2. Counting Lines with awk

awk is a powerful text processing tool in Unix/Linux that is primarily used for pattern scanning and processing. It is especially useful for extracting and reporting specific parts of file content. One of its many capabilities includes counting the number of lines in a file efficiently.

  1. Open your terminal.
  2. Run the following command to count line:
awk 'END {print NR}' filename

Replace filename with the name of your file.

The command will output the total number of lines in the file.

viewing total number of lines in a file using awk
  1. To count lines in multiple files:
awk 'FNR==1{print ""; print FILENAME} {print FNR, $0}' file1 file2

This example prints the filename followed by each line number and content for multiple files.

counting lines of multiple files using awk 1

3. Using sed for Line Counting

sed is a stream editor used to perform basic text transformations on an input stream (a file or input from a pipeline). It is commonly used for text substitution and deletion. It can also be used to count lines in a file.

  1. Access your command window and run the following command to count lines:
sed -n '$=' filename

Replace filename with the name of your file. The command will output the total number of lines in the file.

counting lines of a file using sed

4. Line Counting with grep

grep is a command-line utility used for searching plain-text data sets for lines that match a regular expression. While it is primarily used for searching, it can also be adapted to count lines.

  1. Launch your Terminal and execute the following command:
grep -c '' filename

Replace filename with the name of your file.

counting lines of a file using grep

5. Using perl for Counting Lines

perl is a highly capable, feature-rich programming language with over 30 years of development. It excels at text processing and is used extensively for system administration, web development, and network programming.

  1. In your Terminal, run the perl command to count lines:
perl -lne 'END {print $.}' filename

Replace filename with the name of your file.

counting lines of a file using perl

6. Sublime Text Editor

Many text editors and Integrated Development Environments (IDEs) come equipped with built-in line-counting features, making line counting even more accessible. These tools provide line-counting capabilities and offer customization options for enhanced file management and manipulation. To count lines in file Linux using Sublime Text, follow these user-friendly steps:

  1. Right-click on the file you want to open and select open with other applications.
opening a text file with other application
  1. Open text file with Sublime Text.
opening text file with sublime text 1
  1. Navigate to the bottom of the file to view the total number of lines in the file.
viewing total line numbers in the file

7. Using Python Script

Programming languages like Python programmable solutions for line counting. By utilizing the file handling capabilities of these languages, you can easily count lines in a file. Follow these steps to count lines in file python:

  1. To count the numbers of lines in a file, create following script :
line_count = 0
with open('filename') as file:
for line in file:
line_count += 1
print("Line count:", line_count)

Replace filename in the code with the actual name of the file you want to count lines for. 

creating python script to count lines
  1. Run the Python script and the program will open the file, iterate through each line, and increment the line_count variable.
executing python script

8. Online Tools and APIs

Online tools and APIs provide a convenient way to count lines in a file without installing or programming. Online line-counting tools are particularly helpful when you don’t have access to command-line tools or prefer a browser-based solution for line-counting tasks. Here is a step-by-step guide to using the online tool to count lines in a file:

  1. Visit the website of the online line counting tool (PREPOSTSEO) you prefer.
visiting online counter tool
  1. Paste the text file of which you want to count the number of lines in the given text box.The online tool will process the text and display the line count along with any additional information or statistics, depending on the tool.
counting text lines using online tool

Counting Lines in Large Files Efficiently

Counting lines in large files can be tricky due to their size. Here are some common problems you might face:

  • Memory Usage: Large files can use a lot of memory, slowing down your system.
  • Processing Time: It takes longer to read and process large files, especially if they have millions of lines.
  • System Load: Running commands on large files can strain your CPU and disk, affecting the performance of other tasks.

Best Practices for Efficient Line Counting

To count lines in large files efficiently, follow these best practices:

  1. Use the wc Command: The wc (word count) command is simple and optimized for performance. It reads the file line-by-line without loading it all into memory. For example, you can use wc -l largefile.txt to quickly count lines and print the total.
  2. Use pv for Progress Monitoring: The pv (pipe viewer) command shows the progress of data through a pipeline. It’s helpful for large files to see the processing status. You can use it with wc like this: pv largefile.txt | wc -l to monitor progress while counting lines.
  3. Process in Chunks with split: If a file is too big, split it into smaller chunks. Use the split command to break it into manageable parts, for example, split -l 1000000 largefile.txt part_. This splits largefile.txt into chunks of 1,000,000 lines each. Then, count lines in each chunk using wc -l part_*.
  4. Use Efficient Tools Like awk or sed: Tools like awk and sed can handle large files efficiently because they process data streamingly. For instance, awk 'END {print NR}' largefile.txt counts lines without high memory usage.
  5. Avoid Loading Entire File into Memory: Make sure your method reads the file line-by-line instead of loading it all into memory. Commands like wc, awk, and sed do this naturally, ensuring efficient use of memory and processing power.

Linux Count Lines in File: Wrapping Up

In this article, I’ve explored several methods to count lines in a file using tools like wc, awk, sed, grep, and scripting languages like Python and Perl. I have also discussed handling large files efficiently, ensuring minimal system resource usage, and troubleshooting common errors to ensure accurate results.

For further learning, I recommend:

Frequently Asked Questions

Is there a way to exclude empty lines or specific characters from the line count?

Yes, most line counting tools and programming solutions offer options to exclude empty lines or specific characters from the count. These options allow you to customize the line counting process based on your requirements. For instance, command-line tools like wc often provide flags or parameters to exclude empty lines or specific characters from the line count. Similarly, when using programming languages, you can implement logic to filter out empty lines or specific characters while iterating through the file.

Can I count lines in compressed files, such as ZIP or GZIP archives?

Yes, it is possible to count lines in compressed files like ZIP or GZIP archives. However, the approach may differ depending on the tools or libraries you use. Some line counting tools have built-in support for handling compressed files, allowing you to count lines without extracting the entire archive. Additionally, certain programming libraries provide functionalities to handle compressed files directly, enabling you to extract the files and count the lines within them programmatically.

Are there any limitations or performance issues when dealing with extremely large files?

When dealing with extremely large files, there may be limitations and performance issues to consider. Memory usage and processing time can become challenges as the size of the file increases. It is recommended to employ memory-efficient algorithms and techniques to minimize memory consumption during the line counting process. Streaming techniques, where the file is read in chunks instead of loading it entirely into memory, can be useful for handling large-scale line counting efficiently. Additionally, leveraging parallel processing capabilities, such as distributing the line counting task across multiple threads or machines, can help improve performance when dealing with extremely large files.

Ojash

Author

Ojash is a skilled Linux expert and tech writer with over a decade of experience. He has extensive knowledge of Linux's file system, command-line interface, and software installations. Ojash is also an expert in shell scripting and automation, with experience in Bash, Python, and Perl. He has published numerous articles on Linux in various online publications, making him a valuable resource for both seasoned Linux users and beginners. Ojash is also an active member of the Linux community and participates in Linux forums.

Akshat

Reviewer

Akshat is a software engineer, product designer and the co-founder of Scrutify. He's an experienced Linux professional and the senior editor of this blog. He is also an open-source contributor to many projects on Github and has written several technical guides on Linux. Apart from that, he’s also actively sharing his ideas and tutorials on Medium and Attirer. As the editor of this blog, Akshat brings his wealth of knowledge and experience to provide readers with valuable insights and advice on a wide range of Linux-related topics.

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