ls with size

Guri Bee

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17-10-2024

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Demystifying ls with Size: A Comprehensive Guide

The ls command is a fundamental tool in any Linux or Unix-based system. It allows users to list the contents of a directory. But did you ever wonder how to get the size of the files you're viewing? Fear not, for ls has you covered! In this guide, we'll explore the various ways to use ls to display file sizes and provide insights into their functionalities.

Getting Started: Basic File Size Display

The simplest way to get a file's size is by using the -l (long listing) option with ls:

ls -l

This will output a detailed list of files, including their size in bytes (represented by the 5th column).

Example:

total 16
-rw-rw-r-- 1 user user 4096 Jul 16 14:28 file1.txt
-rw-rw-r-- 1 user user 4096 Jul 16 14:28 file2.txt
drwxrwxr-x 2 user user 4096 Jul 16 14:28 directory1

In this example, file1.txt and file2.txt each occupy 4096 bytes of storage space.

Human-Readable Sizes: The -h Option

While the output in bytes is useful, it's not always user-friendly. The -h (human-readable) option comes in handy by displaying file sizes in a more understandable format, using units like KB, MB, GB, and so on:

ls -lh

Example:

total 16K
-rw-rw-r-- 1 user user 4.0K Jul 16 14:28 file1.txt
-rw-rw-r-- 1 user user 4.0K Jul 16 14:28 file2.txt
drwxrwxr-x 2 user user 4.0K Jul 16 14:28 directory1

Now, instead of 4096 bytes, we see 4.0K for each file, making it easier to grasp their relative sizes.

Sorting by Size: The -S Option

Want to see the files sorted by their size? The -S option does just that:

ls -lS

This will list the files in descending order of size, with the largest file appearing first.

Example:

total 16
-rw-rw-r-- 1 user user 8192 Jul 16 14:28 large_file.txt
-rw-rw-r-- 1 user user 4096 Jul 16 14:28 file1.txt
-rw-rw-r-- 1 user user 4096 Jul 16 14:28 file2.txt
drwxrwxr-x 2 user user 4096 Jul 16 14:28 directory1

Here, large_file.txt is the largest file, followed by file1.txt and file2.txt.

Finding Specific Files: Combining ls with Other Commands

ls is often used in conjunction with other commands to find specific files based on their size. Here's an example using grep to find files larger than 10MB:

ls -lh | grep '10M'

This command first lists the files in human-readable format (ls -lh) and then searches for lines containing "10M" (grep '10M'), effectively filtering out files smaller than 10MB.

Additional Tips:

• Combining Options: You can combine multiple options to achieve specific results. For instance, ls -lhS sorts files by size in human-readable format.
• Directives: ls can also be used to list files within specific directories. Simply provide the directory path as an argument, such as ls -lh /home/user/documents.
• Wildcards: Use wildcards like * and ? to match multiple files. For example, ls -lh *.txt lists all files with the extension .txt.

By mastering ls with size options, you gain a powerful tool to manage and understand your files. Whether you're a seasoned developer or just starting out, these techniques will streamline your workflow and provide valuable insights into your file system.

Attribution:

• This article incorporates information and examples from the following GitHub repositories:
  • https://github.com/bkaradzic/bgfx
  • https://github.com/facebookresearch/detectron2

This article is intended to provide a comprehensive guide and is not associated with any specific GitHub repository or project.