Create user, set password
useradd test
passwd test
Join user group-G is for additional user group
usermod -G root test
newgrp root
View current user group
gropus [user]
Modify file
vim /etc/sudoers
test ALL = (ALL) ALL
chmod -R current directory and subdirectories
| 7 | Read + write + execute | rwx | 111 |
| 6 | Read + write | rw- | 110 |
| 5 | Read + execute | r-x | 101 |
| 4 | Read only | r-- | 100 |
| 3 | Write + execute | -wx | 011 |
| 2 | just write | -w- | 010 |
| 1 | Execute only | --x | 001 |
| 0 | no |