to make a new user>>> useradd
change password>> passwd “existing username”
to create a group>> groupadd
create a new user and put in the existing group>> useradd “groupname” “username”
to add an existing user into an existing group >> usermod –G “groupname” “username”
To check the list of permission >>> ls –l
to change permission we use 777 (rwx rwx rwx)
1st 7 for admin user, 2nd 7 for group and 3rd 7 for end users
(r) 4 read only
(w) 2 write permission
(x) 1 execute permission
to change the permission use >>> chmod 777 “group” or “user Name”
To see encrypted password >> <etc> cat shadow
to see groups permission info >> <etc> cat group (first field username : 2nd password :3rd ID number: 4th member of groups)