The e4defrag command in Linux is a command-line utility that is used to defragment ext4 file systems. This command can be used to optimize the performance of an ext4 file system by rearranging the files and directories on the file system to improve the efficiency of read and write operations. The e4defrag command can defragment both regular files and directories, and it can be run on unmounted file system.
It is important to note that the use of e4defrag command requires root or superuser access. Also, the defragment process may take a while depending on the size of the file system and it may not always improve the performance. It’s recommended to backup important data before running the command.
e4defrag Command Examples
1. Defragment the filesystem:
# e4defrag /dev/sdXN
2. See how fragmented a filesystem is:
# e4defrag -c /dev/sdXN
3. Print errors and the fragmentation count before and after each file:
# e4defrag -v /dev/sdXN