How to Split Large Files into Smaller Chunks in Ubuntu

Managing large files on Ubuntu can be challenging when transferring or storing data. This article explains how to use the built-in split command to divide large files into manageable chunks of a specific size. You will learn the basic syntax, common examples, and how to reassemble the original file after splitting.

The Split Command

The primary command for dividing files in Ubuntu is split. It is pre-installed on most Linux distributions. This tool reads a file and writes it in fixed-size chunks to one or more output files.

Basic Syntax

The general structure for the command is:

split [OPTION]... [INPUT [PREFIX]]

To split a file by size, use the -b flag followed by the desired size.

Splitting by Specific Size

To split a large file into 100 megabyte chunks, run the following command:

split -b 100M largefile.zip part_

This creates files named part_aa, part_ab, part_ac, and so on. You can customize the prefix part_ to any name you prefer.

Common Size Units

When specifying size, you can use the following suffixes:

• b for 512-byte blocks
• K for kilobytes
• M for megabytes
• G for gigabytes

For example, to split a video file into 1 gigabyte parts:

split -b 1G video.mp4 video_chunk_

Reassembling the File

To restore the original file from the chunks, use the cat command. Ensure you are in the directory containing the split parts and run:

cat part_* > largefile.zip

Replace part_* with the prefix you used during splitting. This command concatenates all parts in alphabetical order back into the single original file.

Verifying the Output

After reassembling, it is good practice to verify the file integrity. You can compare the checksum of the new file against the original if you saved it beforehand. Use the md5sum command to generate a hash for verification.

md5sum largefile.zip

This ensures that no data was lost or corrupted during the splitting and merging process.