I am a newbie to ROS and know absolutely nothing about it. I am following this tutorial and at 5:33 he enters the following command rosmsg show std_msgs/ and when I do the same in the terminal i get the following error, and I am not sure what the problem is. I have tried looking for an answer in other places but I couldn't find anything. Any help would be much appreciated.


Unable to load msg [std_msgs/]: Cannot locate message [] in package [std_msgs] with paths [['/opt/ros/noetic/share/std_msgs/msg']]

1 Answer 1


The user in the video is pressing the tab key to get a list of possible completions of rosmsg show std_msgs/, you are pressing 'enter' and tring to execute that command, but it's invalid, it wants a specific message to show. (It'd be helpful if the video creator was using a program to show which keys they were pressing on screen)

rosmsg show std_msgs/

don't press enter, press tab, then get this output:

std_msgs/Bool                 std_msgs/Empty                std_msgs/Int16                std_msgs/Int8                 std_msgs/UInt16               std_msgs/UInt8
std_msgs/Byte                 std_msgs/Float32              std_msgs/Int16MultiArray      std_msgs/Int8MultiArray       std_msgs/UInt16MultiArray     std_msgs/UInt8MultiArray
std_msgs/ByteMultiArray       std_msgs/Float32MultiArray    std_msgs/Int32                std_msgs/MultiArrayDimension  std_msgs/UInt32               
std_msgs/Char                 std_msgs/Float64              std_msgs/Int32MultiArray      std_msgs/MultiArrayLayout     std_msgs/UInt32MultiArray     
std_msgs/ColorRGBA            std_msgs/Float64MultiArray    std_msgs/Int64                std_msgs/String               std_msgs/UInt64               
std_msgs/Duration             std_msgs/Header               std_msgs/Int64MultiArray      std_msgs/Time                 std_msgs/UInt64MultiArray

I usually do this to get a list of possible messages without using the tab completion:

rosmsg list | grep std_msgs
  • $\begingroup$ Thank you so much. I thought I was going crazy haha. $\endgroup$
    – Balen
    Dec 11, 2023 at 14:45

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