Deleting Large Files Programmatically in CentOS 7 with Shell Scripting

In many scenarios, managing disk space is crucial for maintaining the efficiency and performance of a server. One effective method is to automate the process of deleting large files that do not require retention. This article will guide you through writing a shell script to delete files larger than a specified size in CentOS 7.

Step-by-Step Guide

Decide on the Size Limit

First, determine the file size limit you want to enforce. For this example, let's set it to 100MB. You can adjust the size limit based on your specific requirements.

Choose the Directory

Next, decide which directory to search for large files. Typically, this would be a directory where unneeded large files are more likely to accumulate.

Create the Shell Script

To create the shell script, follow these steps using a text editor such as vim or nano. Here is an example script:

#!/bin/bash# Directory to searchDIRECTORY/path/to/directory# Size limit in bytes (100MB  104857600 bytes)SIZE_LIMIT104857600# Find and delete files larger than SIZE_LIMITfind $DIRECTORY -type f -size  $SIZE_LIMIT -exec rm -f {}  

Explanation

The script begins with #!/bin/bash, indicating that the script should be executed using the Bash shell.

Directory to search: Modify /path/to/directory to the actual path of the directory you want to search. Size limit: The size limit is set to 100MB, which translates to 104,857,600 bytes. find command: This command searches for files larger than the specified size and executes the rm -f {} command on them.

The -exec option runs the rm -f command on each file found by find. The {} is a placeholder for the file name, and is used to optimize the process by passing multiple file names to the rm command in a single invocation, rather than starting a new process for each file.

Usage

To use the script:

Save the script to a file, for example, delete_large_ Make the script executable using the command chmod x delete_large_ Run the script with ./delete_large_

Important Note: This script will permanently delete files. It is crucial to ensure you have backups or are confident about the files that will be deleted before running the script.

Alternative Solutions

Bill Thompson suggested alternative solutions for handling file names with whitespace:

Command-Line Solution

find . -type f -size 5000c -print0 | xargs -0 rm

This command uses -print0 to separate file names with ASCII NUL characters, which xargs -0 then splits correctly, even for file names with whitespace.

Scripts Using Alternative Commands

find . -type f -size 50000c -exec rm -f {}  

This script directly executes rm -f {} for each file found, which is slightly less efficient but simpler to use.

Multiple File Deletion

find . -type f -size 5000c -exec rm -f {}  

This version is optimized for multiple file deletions, as it uses {} placeholders to pass multiple file names to a single rm command.

By following these guidelines and adapting the scripts as necessary, you can effectively manage file sizes on your CentOS 7 system and maintain disk space efficiently.