csplit is a popular utility in Linux that splits the given text file into multiple individual files. The file to split must be a text file. By default, the csplit command names the output files as “xx00”, “xx01”, “xx02”, and so on. However, we can also specify a prefix of our choice (if needed). This command line utility can accept different flags or options to customize/modify the output according to users’ needs.
Splitting Files on Linux Using csplit
The csplit command in Linux refers to “split by context”. This command lets us split or break a file into sections based on context lines, such as line numbers or patterns.
csplit Command Basic Syntax
To use csplit command in Linux, you must follow the below syntax:
csplit [OPTION]... fileName PATTERN...
Here, “OPTION” represents optional flags or arguments used to customize the behavior of the csplit command. “fileName” is a target text file that needs to be split into several sections/subfiles. “PATTERN” represents a pattern or line number based on which the given file will split.
csplit Command Options
The csplit command can accept different options to perform various functionalities. Some widely used options of the csplit command are listed below:
| Option | Description |
| -b, suffix-format | It specifies the sprintf FORMAT in place of “%02d”. |
| -f, –prefix | It uses a user-defined prefix for the output files instead of the default prefix “xx”. |
| -k, –keep-files | It doesn’t remove the output file if an error occurs. |
| –suppress-matched | It skips a specific line while splitting the target file. |
| -n, –digits | It lets us modify the number of digits in the file name instead of the default 2. |
| -s, –quiet, –silent | It ensures file splits silently without mentioning output file sizes. |
| -z, –elide-empty-files | It ensures the removal of empty output files. |
| –help | It shows the help page of the csplit command, containing information about command usage, option details, pattern details, and more. |
| –version | It retrieves the installed version of the csplit command. |
csplit Command Man Page
For more detailed information, you can access the official manual page of the csplit command by running the following command in the terminal:
man csplit
csplit Installation on Linux
Generally, the csplit command comes pre-installed on all Linux distributions. However, for some reason, if this command is not installed on your system, you can easily install it using a package manager like apt, yum, dnf, etc., depending upon your Linux distribution. The below snippet shows how to install csplit command on different Linux distributions:
#Debian-based systems
sudo apt install coreutils
#Arch Linux
sudo pacman -S coreutils
#Fedora and RHEL
sudo dnf install coreutils
How Does csplit Work on Linux?
Let’s look at some examples to understand how the csplit command operates in Linux, with or without options. For this purpose, first, create a text file and specify some content in it. The following shows the content of a sampleFile.txt:
cat sampleFile.txt
In the following examples, we’ll use the csplit command to split this file into multiple sections.
Example 1: Splitting a File Using csplit Command
Let’s run the csplit command without any option to see how it splits the specified file by default:
csplit sampleFile.txt 3
This command splits the sampleFile.txt from the third line, as shown in the following screenshot:
You can view the content of split files using the cat command as follows:
cat xx00
cat xx01
The output confirms that the selected file has been split into two files. The content of the second file “xx01” starts from the third line of sampleFile as specified in the csplit command:
Example 2: Splitting a File With Specific Prefixes
We can use the “-f” flag with the csplit command to specify prefixes of our choices in the file names. For instance, in the following example, we use “file” as a prefix instead of the default “xx”:
csplit -f file sampleFile.txt 3
From the output you can see that this time split files are prefixed with “file” instead of “xx”:
Example 3: Keeping the Output Files When Some Errors Occur
By default, when an error occurs in the csplit command, it removes the output files. However, if we specify the -k option with the csplit command, it doesn’t remove output files. For instance, we run the below-mentioned erroneous command:
csplit -k sampleFile.txt 2 {2}
The following output shows that an error occurs while executing the csplit command. However, the csplit command keeps the split files because of the -k option:
Example 4: Modifying the Number of Digits in the Split Filenames
The -n option with the csplit command lets us specify the number of digits to be used in the output (split) filenames. By default, csplit uses two digits (i.e., xx00, xx01), but we can modify this to use more or fewer digits as needed. For instance, in the following command, we specify -n 3, which ensures that the split filenames will have three digits:
csplit -n 3 sampleFile.txt 3
Example 5: Split Files Silently Without Showing the Sizes
In the previous example, you may have noticed that the csplit command shows the size count of the output files. If we don’t want to see these size counts, we can use the -s option with the csplit command, as follows:
csplit -s sampleFile.txt 3
The output ensures that this time the csplit command executes silently:
Example 5: Omitting a Specific Line From the Output Files
If we need to skip specific lines while splitting a file into sections, we should use the –suppress-matched option with the csplit command. For instance, the following command omits line 3 from the split output files:
csplit --suppress-matched sampleFile.txt 3
The output confirms that the csplit command skips the third line from the output files:
Example 6: Checking the csplit Version
To check which version of the csplit command you are using, run the csplit command with the –version option, as follows:
csplit --version
Example 7: Accessing the csplit Command Help Page
To learn more about the available options and their working, run the csplit command with the “–help” option, as follows:
csplit --help
Difference Between split and csplit Command
In Linux, both the split and csplit commands are used to split files into smaller files. However, they differ in their functionality. The split command divides files based on byte size or line count, which is useful for splitting files into fixed-size chunks but does not consider content. In contrast, the csplit command can split files based on content patterns or specific line numbers, making it useful for scenarios where you need to divide a file according to its content rather than its size.
Conclusion
csplit is a commonly used command in Linux that splits text files into smaller sections based on specific patterns or line numbers. The csplit command offers various options and flags that are used to customize its behavior. Using these options, we can change output file prefixes, modify filename digits, suppress error messages, etc. This tutorial covered the basic syntax of the csplit command, its various options, practical examples, and how to customize its behavior.
