Windows Command Line - Hiding a file or virus

attrib Attribute

h --> hidden

r --> read only

s --> system attribute

+/- --> set/clear

attrib +h Test.txt
attrib -h Test.txt

attrib +r Test.txt
attrib -r Test.txt

attrib +s Test.txt
attrib -s Test.txt

attrib +h +r +s Test.txt #You can not find it anymore.
attrib -h -r -s Test.txt