Command Line Basics (Mac)

pwd
print working directory
hostname
my computer’s network name
mkdir
make directory
cd
change directory
ls
list directory
rmdir
remove directory
pushd
push directory
popd
pop directory
cp
copy a file or directory
mv
move a file or directory
less
page through a file
cat
print the whole file
xargs
execute arguments
find
find files
grep
find things inside files
man
read a manual page
apropos
find what man page is appropriate
env
look at your environment
echo
print some arguments
export
export/set a new environment variable
exit
exit the shell
sudo
DANGER! become super user root DANGER!
chmod
change permission modifiers
chown
change ownership

Source:
Learn Code the Hard Way