filefrag

Filefrag is a command line tool in Linux that displays the fragmentation information for a given file or set of files. It provides details about the fragmentation status of the file, which can be helpful for optimizing performance and disk usage. The tool analyzes the file's data blocks and provides information such as the number of extents, the location of each extent, the size of each extent, and how fragmented the file is.

Filefrag can be used to determine if a file is heavily fragmented, which can result in slower access times. By knowing the fragmentation level, users can decide whether to defragment the file or take other actions to improve disk performance. Additionally, it can help in identifying files that are spread across multiple disk locations, called extents, which can also affect performance.

The output of filefrag includes various columns for each extent, like the logical and physical offset, the length of the extent in bytes, the file's size, and the fragmentation status. It also provides a summary that includes details about the total number of extents, the fragmentation level (measured in percentage), the file's size, and the path of the file.

Filefrag supports a range of options such as -v for verbose output, -e for detailed information on each extent, and -b to display the status in terms of filesystem blocks instead of bytes. It can be used on individual files or directories, and even specific device files.

Overall, filefrag is a useful tool for analyzing file fragmentation and can contribute to better disk performance and optimization in Linux systems.