ls

list directory contents (ls -l, long listing format; ls -a, list all files including those starting with ".") 

pwd

print name of working (current) directory

mkdir dirname

make a directory (e.g., dirname)

cd dirname

change current directory to dirname (also, chdir dirname)

rm filename

remove (delete) filename permanently;  rm -r (recursive) deletes directories and contents 

more filename

displays file one screen at a time (less is a similar command)

cp

copy file, requires added information. Examples:

   cp tom.html dick.html  (makes a copy in the same directory)

   cp tom.html project/dick.html (makes a copy in the project directory)

mv

move a file or directory

man command

manual pages (help) on a command; for example, man ls

joe filename

use joe to edit file; also pico filename, emacs filename, ....