Files
PhotonVision/docs/source/docs/troubleshooting/unix-commands.md
2025-05-07 16:09:11 -05:00

133 lines
4.4 KiB
Markdown

# Useful Unix Commands
## Networking
### SSH
[SSH (Secure Shell)](https://www.mankier.com/1/ssh) is used to securely connect from a local to a remote system (ex. from a laptop to a coprocessor). Unlike other commands on this page, ssh is not Unix specific and can be done on Windows and MacOS from their respective terminals.
:::{note}
You may see a warning similar to `The authenticity of host 'xxx' can't be established...` or `WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!`, in most cases this can be safely ignored if you have confirmed that you are connecting to the correct host over a secure connection, and the fingerprint will change when your operating system is reinstalled or PhotonVision's coprocessor image is re-flashed. This can also occur if you have multiple coprocessors with the same hostname on your network. You can read more about it [here](https://superuser.com/questions/421997/what-is-a-ssh-key-fingerprint-and-how-is-it-generated)
:::
Example:
```
ssh pi@hostname
```
For PhotonVision, the username will be `pi` and the password will be `raspberry`.
### ip
Run [ip address](https://www.mankier.com/8/ip) with your coprocessor connected to a monitor in order to see its IP address and other network configuration information.
Your output might look something like this:
```
2: end1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether de:9a:8f:7d:31:aa brd ff:ff:ff:ff:ff:ff
inet 10.88.47.12/24 brd 10.88.47.255 scope global dynamic noprefixroute end1
valid_lft 27367sec preferred_lft 27367sec
```
In this example, the numbers following `inet` (10.88.47.12) are your IP address.
### ping
[ping](https://www.mankier.com/8/ping) is a command-line utility used to test the reachability of a host on an IP network. It also measures the round-trip time for messages sent from the originating host to a destination computer. It can be used to determine if a network interface is available, which can be helpful when debugging.
## File Transfer
All files under `/opt/photonvision` are owned by the root user. This means that if you want to modify them, the commands to do so must be ran as sudo.
### SCP
[SCP (Secure Copy)](https://www.mankier.com/1/scp) is used to securely transfer files between local and remote systems.
Example:
```
scp [file] pi@hostname:/path/to/destination
```
### SFTP
[SFTP (SSH File Transfer Protocol)](https://www.mankier.com/1/sftp#) is another option for transferring files between local and remote systems.
### Filezilla
[Filezilla](https://filezilla-project.org/) is a GUI alternative to SCP and SFTP. It is available for Windows, MacOS, and Linux.
## Miscellaneous
### v4l2-ctl
[v4l2-ctl](https://www.mankier.com/1/v4l2-ctl) is a command-line tool for controlling video devices.
List available video devices (used to verify the device recognized a connected camera):
```
v4l2-ctl --list-devices
```
List supported formats and resolutions for a specific video device:
```
v4l2-ctl --list-formats-ext --device /path/to/video_device
```
List all video device's controls and their values:
```
v4l2-ctl --list-ctrls --device path/to/video_device
```
:::{note}
This command is especially useful in helping to debug when certain camera controls, like exposure, aren't behaving as expected. If you see an error in the logs similar to `WARNING 30: failed to set property [property name] (UsbCameraImpl.cpp:646)`, that means that PhotonVision is trying to use a control that doesn't exist or has a different name on your hardware. If you encounter this issue, please [file an issue](https://github.com/PhotonVision/photonvision/issues) with the necessary logs and output of the `v4l2-ctl --list-ctrls` command.
:::
### systemctl
[systemctl](https://www.mankier.com/1/systemctl) is a command that controls the `systemd` system and service manager.
Start PhotonVision:
```
systemctl start photonvision
```
Stop PhotonVision:
```
systemctl stop photonvision
```
Restart PhotonVision:
```
systemctl restart photonvision
```
Check the status of PhotonVision:
```
systemctl status photonvision
```
### journalctl
[journalctl](https://www.mankier.com/1/journalctl) is a command that queries the systemd journal, which is a logging system used by many Linux distributions.
View the PhotonVision logs:
```
journalctl -u photonvision
```
View the PhotonVision logs in real-time:
```
journalctl -u photonvision -f
```