vi foo.txt
--

 -- in and out :q!
 -- cmd mode vs insert mode
 -- cursor movement hjkl
 -- i : insert mode
 -- a : append mode
 -- :q!		no write and quit
 -- :wq!	write quit 
 -- x		cmd mode to remove one character
 -- 5x		remove 5 characters
 -- dd		delete one line
 -- 2dd		delete two lines
 -- dw		delete one word
 -- y		yank
 -- yw		yank a word
 -- 2yy		yank 2 lines
 -- p		paste
 -- $		to end
 -- 0		to front
 -- /		search then n to next
 -- u		command mode undo

 -- modify something and save
 -- esc		insert mode --> cmd mode


echo

env variable
--
echo $SHELL
echo $HOME

vi ~/.bashrc
PS1="hello-> "
:wq!
source ~/.bashrc

mouse copy paste
mouse left drag (copy)
mouse right click (paste)

mkdir		make a directory
rmdir		remove a directory, cannot remove empty dir, use rm -fr to remove a non empty dir
cd		change directory
rm		remove a file
rm -fr		force to remove whole directory
pwd		show currrent directory
cd ..		move up directory
cd ~		cd to HOME directory just like cd

change bash system prompt
source ~/.bashrc

ssh s3121@21.33.59.152

pkg search sudo		# search for database
pkg install -y sudo
vi /usr/local/etc/sudoers
/ search wheel
#%wheel ALL=(ALL) ALL # orig, remove 1st #
%wheel ALL=(ALL) ALL

pkg info | grep sudo	# search for package you are already installed
remove a user
rmuser -y john
ls /home		# check users

login as regular user
how to become root	# use sudo
sudo su			# type user password to enter
# exit			# exit root, note: root prompt is # user prompt $

note: in config file # means comment, ignore it

scp in mobaxTerm

homework 2: create 3 users 
--
1. due 2020.09.30 24:00
2. requirement
 2a: 2018-1.txt 2018-2.txt
 group_id, ip
 18101, 21.33.59.152

 2b.
 cpfong account exists

 2c. 
 two user have been created

 2d. 
 group wheel
 login ok and has supervisor privilege

--ref
Full name: john chen
Uid (Leave empty for default):
Login group [zyz]: wheel
Login group is wheel. Invite zyz into other groups? []:
Login class [default]:
Shell (sh csh tcsh bash rbash git-shell nologin) [sh]: csh
Home directory [/home/zyz]:
Home directory permissions (Leave empty for default):
Use password-based authentication? [yes]:
Use an empty password? (yes/no) [no]:
Use a random password? (yes/no) [no]:
Enter password:
Enter password again:
Lock out the account after creation? [no]:
Username   : zyz
Password   : *****
Full Name  : john chen
Uid        : 1004
Class      :
Groups     : wheel
Home       : /home/zyz
Home Mode  :
Shell      : /bin/csh
Locked     : no
OK? (yes/no):

how to check cpfong in right permission ?
--
cpfong@iZbp1a9uy8axsb1zc2i2lqZ:/root % cd ~cpfong
cpfong@iZbp1a9uy8axsb1zc2i2lqZ:~ % pwd
/usr/home/cpfong
cpfong@iZbp1a9uy8axsb1zc2i2lqZ:~ % ls -la
total 48
-rw-r--r--  1 cpfong  cpfong  1055 Sep 23 12:15 .cshrc # Wrong!! group is cpfong not wheel


# cd /root
# ls -la
total 88
drwxr-xr-x   6 root  wheel   512  9月 24 20:35 .
drwxr-xr-x  19 root  wheel  1024  8月  5 17:08 .. # correct!!