e4defrag:tldr:13a20

The command "e4defrag -c ${-dev-sdXN}" is used to defragment an ext4 file system on a specific device partition. Here is a breakdown of each component:

• "e4defrag": This is the command utility for defragmenting ext4 file systems in Linux. It is specifically designed for defragmenting ext4 file systems and is different from general-purpose defragmentation tools.
• "-c": This flag is used to specify the defragmentation mode as "consolidation". It ensures that all free space is moved to the end of the file system, reducing fragmentation.
• "${-dev-sdXN}": This is a placeholder indicating the specific device and partition where the ext4 file system is located. The "sdX" refers to the device letter (e.g., sda, sdb, etc.), and "N" represents the partition number. You need to replace "sdXN" with the actual device and partition you want to defragment.

In summary, the command "e4defrag -c ${-dev-sdXN}" is used to defragment an ext4 file system on a specified device partition, by consolidating free space at the end of the file system.