To find and report on file fragmentation in Linux, you can use the filefrag command. This command analyzes the layout of a file on disk and reports on the level of fragmentation.
To use filefrag, you can simply run the command followed by the path to the file you want to analyze. For example:
filefrag /path/to/file
This will output information about the file, including the number of extents (continuous blocks of disk space) used by the file, the total number of blocks, and the fragmentation index. The fragmentation index is a measure of how fragmented the file is, with a higher value indicating more fragmentation.
You can also use the -v flag to get a more detailed report, which includes information about the physical location of each extent on the disk.
filefrag -v /path/to/file
Keep in mind that file fragmentation is generally not a concern on modern systems with fast disks and efficient filesystems, as the filesystem will usually try to allocate contiguous blocks of space for new files and defragment existing files as needed. However, if you are experiencing performance issues and suspect file fragmentation may be a factor, the filefrag command can help you identify and potentially resolve the issue.