How To List Files of a Particular Extension in Ubuntu

In the world of Ubuntu, being able to handle files efficiently is a crucial skill. One such task you may often encounter is listing files of a particular extension. This article will guide you through the process, using various commands and techniques.

Introduction

File management is a key aspect of any operating system, and Ubuntu is no exception. Whether you’re a developer looking for all your .php files, a writer searching for your .doc files, or a system administrator trying to locate all .log files, knowing how to list files of a particular extension can save you a lot of time.

Using the ls Command

The ls command is one of the most basic and commonly used commands in Linux. It’s used to list files and directories within a directory. If you want to list all files of a particular extension, you can use the ls command with a wildcard (*). Here’s an example:

ls *.txt

This command will list all files with the .txt extension in the current directory. However, if there are a large number of files, you may encounter an error message “Argument list too long”. This happens because the shell has a limit on the maximum number of arguments it can handle.

Using the find Command

To avoid the “Argument list too long” error, we can use the find command. This command allows you to search for files based on various criteria, including file name patterns. Here’s how you can use find to list all files with the .txt extension:

find . -name "*.txt"

In this command, . indicates the current directory, -name specifies the search criterion (in this case, file name), and "*.txt" is the pattern to match. This command will search for files with the .txt extension in the current directory and its subdirectories.

Executing Commands on Each File

The find command also allows you to execute a command on each file found. To do this, you can use the -exec option as follows:

find . -name "*.txt" -exec COMMAND {} \;

Replace COMMAND with the actual command you want to run on each file. The {} placeholder represents the file name.

Using the shopt Command

Another way to list files of a particular extension is by using the shopt command in bash to enable the nullglob option. This option allows patterns that match no files to expand to an empty list. Here’s an example:

shopt -s nullglob
files=(*.txt)
echo ${#files[@]}

In this command, shopt -s nullglob enables the nullglob option, files=(*.txt) stores the file names in an array, and echo ${#files[@]} prints the number of elements in the array.

Conclusion

In this article, we have covered how to list files of a particular extension in Ubuntu using the ls, find, and shopt commands. We’ve also discussed how to execute commands on each file found. With these skills, you should be able to handle files more efficiently in Ubuntu.

Remember, parsing the output of ls is generally not recommended, as it can be unreliable and may cause issues with filenames containing special characters. The find command and the shopt option provide more robust and reliable solutions. For more information on these commands, you can check their man pages by typing man find or man shopt in your terminal.