Some awesome Unix / Linux commands

How to open binary file in "vi" in hex mode  

$ vi test.dat

then in vi command mode type ( this may take few seconds)

:%!xxd

if you need to exit type

:%!xxd -r

dd command:

To backup the entire hard disk: 

$ dd if = /dev/sda of = /dev/sdb

if  is the Input file

of is the output file

To copy testfile.dat file to small_testfile.dat

$ dd if=testfile.dat of=small_testfile.dat bs=1000 count=1 

if  is the Input file

of is the output file

bs number of byes/blocks copied <count> number of times i.e 1

How to open home directly on Windows Subsystem for Linux ?

$ explorer.exe .

Don't leave out the "."