Linux commands Part 4

sudo – getting root permissions

ll /etc/passwd

vi /etc/passwd        - Read only file, we cannot write

sudo vi /etc/passwd   - able to write

user and group permissions for files and groups

[opc@new-k8s etc]$ ll /etc/os-release
-rw-r--r--. 1 root root 452 Sep 30  2020 /etc/os-release

Switch user

sudo su

su vignesh

su – vignesh

Creating user

For Ubuntu Operating system

By default useradd command will create a user but will not create home directory

useradd test

To create home directory pass -s or --create-home argument to useradd command

useradd -s test1

Set password for user

passwd test

Verify user

cat /etc/passwd

Test user trying to install tree package

sudo yum install tree – will not work, because test user dosen’t have sudo privileges

Giving Sudo permission to a User

For giving sudo permission to a user, you need to add the user to a respective group based on the operating system

For Centos, oracle Linux os

usermod -aG wheel test

Group Name –> wheel

For Ubuntu os

usermod -aG sudo test

To verify whether user is added to the group

id test

cat /etc/group

Test user trying to install tree package

sudo yum install tree – will work, because test user now have sudo privileges

Remove user from group

gpasswd -d test wheel

gpasswd -d test wheel

Delete the user without deleting any of their files

userdel test

Delete the user’s home directory along with the user account

userdel -r test