Ros2 - common command line (IV)

ROS2 Robot operating system

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Preface

Let's introduce ROS2 Common operation instructions in

One 、 Common command line

cd

grammar ：cd < Directory path >

function ： Change the working directory . If not specified “ Directory path ”, Then return to the user's home directory

pwd

grammar ：pwd
function ： This command shows the absolute path of the current working directory

mkdir

grammar ：mkdir [ Options ] < Directory name >

function ： Create a directory / Folder

ls

grammar ：ls [ Options ] [ Directory name …]

function ： List the contents / List of files in the folder

gedit

grammar ：gedit < File name >

function ： open gedit Editor edit file , If there is no such file, it will be created

mv

grammar ：mv [ Options ] < Source file or directory > < Destination file or directory >

function ： Rename a file or directory or move a file from one directory to another

cp

grammar ：cp [ Options ] < Source file name or directory name > < Destination file name or directory name >

function ： Copy a file or directory to another file or directory , Or copy multiple source files to the target directory

rm

grammar ：rm [ Options ] < File name or directory name …>

function ： The function of this command is to delete one or more files or directories in a directory , It can also delete a directory and all its files and subdirectories . For linked files , Just deleted the link , The original files remain unchanged

sudo

grammar ：sudo [ Options ] [ Instructions ]

function ： Execute instructions with the privileges of the system administrator

Two 、ROS2 The command line in

ROS2 The operation mechanism of the command line is similar to Linux identical , But all operations are integrated in one ros2 In the general order of , The first parameter in the back indicates different operation purposes , such as node Indicates the operation on the node ,topic Indicates the operation of the topic , What is the specific operation , You can also continue to follow a series of parameters .

1. Run the node program

Want to run ROS2 A node in , We can use ros2 run Command to operate , For example, we need to run turtle simulation node and keyboard control node ：

ros2 run turtlesim turtlesim_node
ros2 run turtlesim turtle_teleop_key

2. View node information

Currently running ROS Which nodes are there in the system ？ You can view it like this ：

ros2 node list

If you are interested in a node , Add a info Sons command , You can know its details ：

ros2 node info /turtlesim 

3、 ... and 、 View topic information

There are topics in the current system , Use the following command to view ：

ros2 topic list

I also want to see the message data in a topic , add echo Try the sub command ：

ros2 topic echo /turtle1/pose 

Four 、 Post topic news

ros2 topic pub --rate 1 /turtle1/cmd_vel geometry_msgs/msg/Twist "{linear: {x: 2.0, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 1.8}}"

5、 ... and 、 Send service request

A turtle is too lonely , The simulator also provides a service —— Produce turtles , Let's try service invocation , Another turtle ：

ros2 service call /spawn turtlesim/srv/Spawn "{x: 2, y: 2, theta: 0.2, name: ''}"

6、 ... and 、 Recording control command

There are many data in the operation of the system , If you want to record some data , How about going back to the laboratory to reproduce this data ？ROS2 Medium rosbag The function is still very easy to use , Easily record and play data ：

ros2 bag record /turtle1/cmd_vel
ros2 bag play rosbag2_2022_04_11-17_35_40/rosbag2_2022_04_11-17_35_40_0.db3

summary

These instructions will be used if they are often used