Welcome to University of Victoria Connected and Autonomous Vehicles Club!
This document will introduce the basic concepts of ROS2 to help you quickly get started with ROS2 functionalities related to CAV applications.
The raw documentation can be found here. But we believe less is more, this quick guide can let you get on the track with minimum pre-stage effort and have fun.
The Ubuntu System
If you are already familiar with terminal interactions in the Linux system, you can skip this section.
Users commonly interact with an operating system in two ways: through the GUI interface (also known as desktop operations) and command-line interaction. Essentially, both serve the same purpose—operating software by clicking certain areas or entering specific commands.
When using simulators or debugging real vehicles, we often need to interact directly with the command line. Therefore, understanding basic command-line operations is a prerequisite for further learning ROS2.
At CAV Club, our vehicles run on the Ubuntu 20.04 operating system, so you need to learn the relevant concepts and usage methods.
Basic commands
ls/cd/pwd
Use ls to see what is inside this directory.
$ ls
f1tenth Desktop Downloads ...Use pwd to see which directory you are in currently.
$ pwd
/home/f1tenthUse cd to change your working directory.
$ cd f1tenth
$ pwd
/home/f1tenth/f1tenthsource
Source is one the commands to execute some commands in a file. You will need to use source to add ros2 to your system path. Path is the directory where the system will find the executable in. After installation, the ROS2 will be in the /opt/ros/foxy. If you do not add this directory to path, system will not be able to find the program.
$ ros2 -h
-bash: ros2: command not found$ source /opt/ros/foxy/setup.bash
$ ros2 -h
usage: ros2 [-h] Call `ros2 <command> -h` for more detailed usage. ...apt
apt is the package manager for Ubuntu system. You can treat it like an App Store which can install the software you want to use.
apt install nano
[sudo] password for <username>:
Reading package lists... Done
Building dependency tree
Reading state information... Done
Suggested packages:
hunspell
The following NEW packages will be installed:
nano
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.sudo
Add sudo prior to your command if you meet permission fault.
$ apt install nano
E: Could not open lock file /var/lib/dpkg/lock-frontend - open (13: Permission denied)
E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), are you root?Add sudo
$ sudo apt install nano
[sudo] password for <username>:
Reading package lists... Done
Building dependency tree
Reading state information... Done
Suggested packages:
hunspell
The following NEW packages will be installed:
nano
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.Useful softwares
cat/vim
cat is a command to display a text file in the command line. vim is a command, as well as a program to edit text files in the command line.
$ ls
Desktop Downloads Pictures sim_ws text.txt Documents Music Public Templates Videos
$ cat text.txt
Hello world!$ vim text.txtHello world!
~
~
~
~
~
"text.txt" 1L, 13C 1,12 AllWhen you are in the vim:
Press i for INSERT mode:
Hello world!
I love CAV Club.
~
~
~
--INSERT-- 3,17 AllPress esc to quit INSERT mode.
Press :q + enter to quit vim without saving.
Press :wq + enter to save and quit vim.
After using wq:
$ vim text.txt
$ cat text.txt
Hello world!
I love CAV Club.