# Roscore fails after restart

I am running ROS Noetic on Ubuntu 20.04.1 LTS

Yesterday I re-installed ROS (it was corrupt) and successfully ran roscore. I left my computer on overnight and this morning it was locked up. I had to do a hard reboot.

Afterwords, when I tried to run roscore, I got the following:

... logging to /home/dtaylor/.ros/log/085907a0-d1ac-11ea-bddb-a1e701cf9cfb/roslaunch-Delta-3256.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

ROS path [0]=/opt/ros/noetic/share/ros
ROS path [1]=/home/dtaylor/catkin_ws/src
ROS path [2]=/opt/ros/noetic/share
The traceback for the exception was written to the log file


The last time this happened, I had to re-install ROS. Is this the only solution?

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It looks like it should be in /opt/ros/noetic/share but it's not. It's also not in /opt/ros/noetic/bin. I did, however, find it in /usr/share and /usr/bin. In /usr/share it is colored blue and in /usr/bin it is colored green. What does that mean?

From what you describe, just as in your previous question (ie: #q356392), you appear to be mixing Noetic packages with wiki/UpstreamPackages.

That will not work, as you've found out.

You'll have to fix this before roscore (and probably other parts of ROS) will start working again.

I added both to my .bachrc file and restarted my terminal but no effect.

This will not affect anything.

more

gvdhoorn, "you appear to be mixing Noetic packages with wiki/UpstreamPackages". I honestly don't remember doing that. I strictly followed the install instructions at http://wiki.ros.org/ROS/Installation. I didn't even know about the upstream packages. Be that as it may, If I do have a mixed environment, how do I fix it? Can I uninstall everything ROS? Would I have to reformat my hard drive and re-install Ubuntu?

( 2020-08-13 13:11:21 -0500 )edit

If you have a roslaunch binary/script in /usr/bin, then you must likely have the python3-roslaunch package installed.

That's not the same package as ros-noetic-roslaunch, which would place roslaunch in /opt/ros/noetic/bin.

Does dpkg -l | grep roslaunch return both python3-roslaunch and ros-noetic-roslaunch for you, or just python3-roslaunch? If the latter, that's why you don't have roslaunch.

As to how you ended up in this situation, I don't know.

Can I uninstall everything ROS?

Yes, you'd essentially remove all ros-noetic-* packages, and afterwards probably all packages which are then no longer needed (apt should tell you).

For the upstream packages, you'd have to figure out which packages you have installed. I don't have any specific advice on how to do that.

Would I have to reformat my hard drive and re-install Ubuntu?

That would be the nuclear option, and technically not ...(more)

( 2020-08-14 06:08:18 -0500 )edit

Did you try source /opt/ros/noetic/setup.bash?

more

Thanks praskot, I had the following in my .bachrc file so I wouldn't have to

source /opt/ros/noetic/setup.bash
source ~/catkin_ws/devel/setup.bash


but, just in case that wasn't working I just tried it and got the same results What can I try next?

( 2020-07-30 14:08:14 -0500 )edit

I'm not really sure, from the error, its not able to find the roslaunch right. Check if you have the roslaunch binary in /opt/ros/noetic/bin. If you do, add it to the path?

( 2020-07-30 14:37:09 -0500 )edit

It looks like it should be in /opt/ros/noetic/share but it's not. It's also not in /opt/ros/noetic/bin. I did, however, find it in /usr/share and /usr/bin. In /usr/share it is colored blue and in /usr/bin it is colored green. What does that mean?

I added both to my .bachrc file and restarted my terminal but no effect.

( 2020-07-31 09:49:06 -0500 )edit

More information... I had the following line in my .bashrc file: export ROS_PACKAGE_PATH=/home/dtaylor/catkin_ws/src:/opt/ros/noetic/share:/usr/share:/usr/bin This doesn't seem to work. When I put it directly in at the command prompt it did find one of the roslaunch things. Still don't know which is the executable. questions:

1. Why does the line not work in my .bashrc file?
2. Why does roslauch keep disappearing from where it is supposed to be?
3. What is the color scheme in ls -a?
( 2020-07-31 09:58:21 -0500 )edit
1. Try adding export ROS_PACKAGE_PATH=/home/dtaylor/catkin_ws/src:/opt/ros/noetic/share:/usr/share:/usr/bin in the bashrc instead?

2. Unfortunately, I have no clue why this is happening

3. As mentioned here https://askubuntu.com/questions/17299/what-do-the-different-colors-mean-in-ls blue implies it is a symbolic link to an executable.

( 2020-07-31 16:57:44 -0500 )edit