extundelete:tldr:f99c8

This command is using the tool extundelete to recover deleted files on a specific disk partition.

Let's break it down:

• extundelete: This is the command-line utility being used for the file recovery.
• ${-dev-sdXN}: This is a placeholder for the path to the disk partition from which you want to recover the files. Replace -dev-sdXN with the actual path of the partition, such as /dev/sda1 or /dev/nvme0n1p3. This line specifies the specific partition or device to work on.
• --restore-all: This option tells extundelete to restore all recovered files. It will attempt to recover and restore any deleted files it finds on the specified partition.
• --after ${1577840400}: This option specifies a condition to only restore files deleted after a specific timestamp. The timestamp provided is in Unix time, which represents the number of seconds elapsed since January 1, 1970. In this case, the timestamp corresponds to January 1, 2020, at 00:00:00 UTC.

So, this command is telling extundelete to recover all deleted files from a specific disk partition, but only those that were deleted after January 1, 2020.