The command inserts a hex e5 (0xe5) in a filename's first letter position in the associated directory entry.

When a file is deleted with the MS-DOS delete command, the hex e5 (0xe5) value tells the OS that the file is unavailable and a new file is ready to be written to the same cluster position. In a FAT file system, when you delete a file, the hex e5 character replaces the 1st letter of the filename and the file of that FAT chain is set to 0