hw2
--
1. cpfong as wheel group
2. sudoers has to be modified

as regular user
--
ls 
ls -l	# l stand for long
ls -la	# a stand for all
ls ~/.*
file, hidden file, dir, . and .. (directory structure)
.	# stand for current dir
..	# stand for parent dir

rw-r--r--    # read write execute / owner group others

cd with tab completion
/etc			# system config
/usr/local/etc		# local config
/var			

permission 
 use echo as an example

 vi foo.sh
  echo 'hello world'

 sh ./foo.sh
 ./foo.sh

chmod			# change file (directory) permission
chmod +x  ./foo.sh	# add execute to everyone
chmod 744 ./foo.sh	# rwx 421 4+2+1=7

for dir	x is enter permission 
chmod 600 x		# you cannot enter x

chmod
https://www.computerhope.com/unix/uchmod.htm

mosh
--
#pkg delete -f pkg ; pkg install pkg ; pkg update -f	#force using new pkg, since old one does NOT work
pkg info | grep mosh
mobaXterm / Sessions / New session / Mosh / ip Username 

Q: why mosh?
A: keep in line

shell
--
echo $SHELL
cd	# change to home dir
cp .cshrc .cshrc.bak	# backup file using copy
ls .cs*			# check for all .cs file
diff .cshrc .cshrc.bak	# check for difference
mv .cshrc.bak .cshrc	# replace .cshrc using .cshrc.bak

vi ~/.cshrc
change alias
alias s sudo		# using s instead sudo

csh
--
find / -name dot.cshrc -type f |& grep dot		#find file and stderr to null

tmux
--
https://www.hamvocke.com/blog/a-quick-and-easy-guide-to-tmux/

vi ~/.tmux.conf

# start
unbind C-b
set -g prefix ^A
bind a send-prefix

set -g status-bg black
set -g status-fg white
# end

split pane
--
Ctrl+a then % 	# left right
Ctrl+a then "	# top down

moving between windows
--
Ctrl+a then arrow key ->

close pane
--
exit

create window
--
Ctrl+a then c

naming window
--
Ctrl+a then ,

moveing 
--
Ctrl+a then 0 1 2 (number)

copy text between windows
--
Ctrl+a [ for copy
Ctrl+a ] for paste

moving using arrow
start to select using space
then using arrow to drag
enter means end of selection