> For the complete documentation index, see [llms.txt](https://b-it-bots.gitbook.io/wiki/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://b-it-bots.gitbook.io/wiki/gitbook-1/_getting-started/tips.md).

# SSH

## Login without entering password

*Credit: Oscar Lima*

This section assumes you already generated ssh keys. You can follow [these](https://help.github.com/articles/generating-ssh-keys) instructions (steps 1 and 2 only).

1. Copy your ssh keys into clipboard and paste the content of your key into the clipboard using the following instructions:

   ```
    sudo apt-get install xclip
    xclip -sel clip < ~/.ssh/id_rsa.pub
   ```
2. ssh into desired pc, e.g.

   ```
    ssh user@youbot-brsu-2-pc1
   ```

   NOTE: you need an account for that on the youbot, if you don't have, you can ask Fred for one
3. Create authorized keys file

   ```
    nano ~/.ssh/authorized_keys
   ```
4. Paste the content of the clipboard there(`ctrl + shift + v`), save (`ctrl + o`, then enter) and close (`ctrl + x`)
5. Give proper permissions to the ssh folder and authorized keys file (current tests indicate this step is not needed)

   ```
    chmod 700 ~/.ssh
    chmod 600 ~/.ssh/authorized_keys
   ```

Done! Now you should be able to log into the robot without entering password

## To open GUI applications in client PC

*Credit: Oscar Lima*

Example: gedit a file on youbot, but display it in your PC

```
    ssh -X youbot-brsu-2-pc1
```

## To tell your computer that the roscore is running on another PC and communicate accordingly trough the network.

*Credit: Oscar Lima*

Example: run some nodes in one computer and other nodes in another computer which can fully communicate with each other.

Drawback: the wifi speed will not allow you to transfer heavy data over the net.

Usage:

1. Set environment variable ROS\_MASTER\_URI to point to the PC in which the roscore is currently running:

   ```
    export ROS_MASTER_URI=http://youbot-brsu-2-pc1:11311
   ```

Done! Now in this terminal in which you executed the command the nodes will communicate with the roscore that is running in another computer.

## Remotely shut down the robot's computer: (requires sudo permission)

*Credit: Oscar Lima*

This assumes you have already ssh'd in the robot's PC

```
    sudo shutdown -h now
```