debugfs [[option] device]

System administration command. Provide direct access to data structure of an ext2 or ext3 filesystem in order to debug problems
with the device. device is the special file corresponding to the device containing the filesystem (e.g., /dev/hda3). debugfs may be used on a mounted filesystem device.

deallocvt N

Deallocate and destroy the unused virtual console /dev/ttyN. Multiple consoles may be named with additional spaces and integers:
deallocvt 1 4 deallocates the /dev/tty1 and /dev/tty4 consoles. Consoles are considered unused if they are not in the foreground,
have no open processes, and have no selected text. The command does not destroy consoles that are still active.

dd options

Make a copy of an input file (if) using the specified conditions, and send the results to the output file (or standard output if of is not
specified). Any number of options can be supplied, although if and of are the most common and are usually specified first. Because dd
can handle arbitrary block sizes, it is useful when converting between raw physical devices.

date [options] [+format] [date]

Print the current date and time. You may specify a display format, which can consist of literal text strings (blanks must be quoted) as well as field descriptors, whose values are described in the following entries (the listing shows some logical groupings). A privileged
user can change the system’s date and time.