> For the complete documentation index, see [llms.txt](https://gitbook.nicacton.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gitbook.nicacton.com/cloud-computing/tutorials-guides/linux/admin.md).

# Admin

## User Administration

#### Add Users

`$ useradd <username>`

#### Make a Group

`$ groupadd <groupname>`

#### Make a User into a SuperUser

`$ usermod -g wheel <username>`

#### Get Information on a User

`$ id <username>`

#### Add User to Group

`$ usermod -aG <groupname> <username>`

#### Lock User Account

`$ usermod -L <username>`

#### Example: Web Admin Group

Setting up a user that can run a limited subset of commands with sudo, add a user to that group.

```
# Create a sudoers entry in the sudoers directory
$ sudo visudo -f /etc/sudoers.d/web_admin
# In the resulting file add the following to set the following allowed commands and user:
Cmnd_Alias WEB = /bin/systemctl restart httpd.service, /bin/systemctl reload httpd.service
<user> ALL=WEB
```

## Secure Shell (SSH)

#### Generate a Key (on Control Station)

`$ ssh-keygen`

#### Copy the SSH key to a Workstation

`$ ssh-copy-id <workstation_ip_or_localname>`

#### Use SSH Agent for Persistent Key Usage

```
# Start your ssh agent
$ eval `ssh agent`
# Load your ssh private key
$ ssh-add <path to private key>
```