topic pub cannot handle multiple `!` lines up in a row

[fujitatomoya]

Bug report

Required Info:

• Operating System:
  • Ubuntu 22.04
• Installation type:
  • source build
• Version or commit hash:
  • rolling:HEAD
• DDS implementation:
  • Any
• Client library (if applicable):
  • rclpy

Steps to reproduce issue

root@tomoyafujita:~/ros2_ws/colcon_ws# ros2 topic echo /chatter
data: Hello ROS
---
data: Hello ROS!
---

root@tomoyafujita:~/ros2_ws/colcon_ws# ros2 topic pub --once /chatter std_msgs/msg/String "data: Hello ROS"
Waiting for at least 1 matching subscription(s)...
Waiting for at least 1 matching subscription(s)...
publisher: beginning loop
publishing #1: std_msgs.msg.String(data='Hello ROS')

root@tomoyafujita:~/ros2_ws/colcon_ws# ros2 topic pub --once /chatter std_msgs/msg/String "data: Hello ROS!"
publisher: beginning loop
publishing #1: std_msgs.msg.String(data='Hello ROS!')

root@tomoyafujita:~/ros2_ws/colcon_ws# ros2 topic pub --once /chatter std_msgs/msg/String "data: Hello ROS!!"
ros2 topic pub --once /chatter std_msgs/msg/String "data: Hello ROSros2 topic pub --once /chatter std_msgs/msg/String "data: Hello ROS!""
usage: ros2 [-h] [--use-python-default-buffering] Call `ros2 <command> -h` for more detailed usage. ...
ros2: error: unrecognized arguments: Hello ROS!

Expected behavior

successfully publishes ros2 topic pub --once /chatter std_msgs/msg/String "data: Hello ROS!!"

Actual behavior

fails to issue the command line.

root@tomoyafujita:~/ros2_ws/colcon_ws# ros2 topic pub --once /chatter std_msgs/msg/String "data: Hello ROS!!"
ros2 topic pub --once /chatter std_msgs/msg/String "data: Hello ROSros2 topic pub --once /chatter std_msgs/msg/String "data: Hello ROS!""
usage: ros2 [-h] [--use-python-default-buffering] Call `ros2 <command> -h` for more detailed usage. ...
ros2: error: unrecognized arguments: Hello ROS!

[fujitatomoya]

@iuhilnehc-ynos any idea?

[iuhilnehc-ynos]

@fujitatomoya

It's not a bug. It's just a feature of bash.

!! in the bash can call the last command, and please see the double quotes.

Enclosing characters in double quotes (‘"’) preserves the literal value of all characters within the quotes, with the exception of ‘$’, ‘`’, ‘\’, and, when history expansion is enabled, ‘!’.

We can use \ or single quotes to avoid this issue.

$ ros2 topic pub --once /chatter std_msgs/msg/String "data: Hello ROS\!\!"
$ ros2 topic pub --once /chatter std_msgs/msg/String 'data: Hello ROS!!'

[fujitatomoya]

@iuhilnehc-ynos thanks for the comment. I actually did not realize that, thanks for the information.