ls
To list the file in your current directory
cd
Change directory
cd ..
Move directory one level upper
man
manual
mv
move files
rm
remove files
exit
does exactly what it means
&
Run the process in the background
ps
list the processess
less
Look at text files
head
Look at the first few lines of a text file
tail
Look at the last few lines of a text file
locate
find files
which
find programs