"/bin/sh: 1: MY_COMMAND: not found"

Question

Error

During docker build -t MY_IMAGE_NAME ., using a Dockerfile for a ROS project, at line

RUN source /opt/ros/melodic/setup.bash

the following error appeared:

 => ERROR [stage-2 19/19] RUN source /opt/ros/melodic/setup.bash 
[...]
#23 0.404 /bin/sh: 1: source: not found
------ executor failed running [/bin/sh -c source /opt/ros/melodic/setup.bash]: exit code: 127

Test

To test this, I created an image of a step before the error step, and checked the command inside the container: and it worked. Thus, the "source" command is available in the bash of the container. How can it be not available in the image, then?

docker run -dit --name MY_CONTAINER_NAME -v /opt/ros/melodic/ MY_IMAGE:latest
docker exec -it MY_CONTAINER_NAME /bin/bash

Fyi: -v /opt/ros/melodic/ mounts the volume -v, else /opt/ros/melodic/ would be empty. By default, only the "build context", in this case where you start the Dockerfile, is not empty.

Now in the container, in the bash (which was loaded using /bin/bash above):

root@1b2bdc5131sy:/# cd opt
root@1b2bdc5131sy:/opt# cd ros
root@1b2bdc5131sy:/opt/ros# ls
melodic
root@1b2bdc5131sy:/opt/ros# cd melodic
root@1b2bdc5131sy:/opt/ros/melodic# ls
_setup_util.py  env.sh  include  local_setup.bash  local_setup.zsh  setup.sh   share
bin             etc     lib      local_setup.sh    setup.bash       setup.zsh
root@1b2bdc5131sy:/opt/ros/melodic# ls
_setup_util.py  env.sh  include  local_setup.bash  local_setup.zsh  setup.sh   share
bin             etc     lib      local_setup.sh    setup.bash       setup.zsh

And I could have just checked it directly anyway, works:

root@1b2bdc5131sy:/# source /opt/ros/melodic/setup.bash    

Question

Since the "source" command works in the container MY_CONTAINER_NAME, how can I get the bash shell working in the underlying image MY_IMAGE_NAME during the docker build of the Dockerfile, instead of using the sh shell?

Solution

Taken from /bin/sh: 1: gvm: not found, which would say more or less:

Your shell is /bin/sh, but source expects /bin/bash, perhaps because it puts its initialization in ~/.bashrc.

In other words, this problem can occur in any setting where the "sh" shell is used instead of the "bash", causing "/bin/sh: 1: MY_COMMAND: not found".

In the Dockerfile case, use the recommended

RUN /bin/bash -c 'source /opt/ros/melodic/setup.bash'

or with the "[]" (which I would rather not use):

RUN ["/bin/bash", "-c", "source /opt/ros/melodic/setup.bash"]

Every new RUN of a bash is isolated, "starting at 0". For example, mind that setting WORKDIR /MY_PROJECT before the bash commands in the Dockerfile does not affect the bash commands since the starting folder would have to be set in the ".bashrc" again. It needs cd /MY_PROJECT even if you have set WORKDIR.

Side-note: do not forget the first "/" before "opt/../...". Else, it will throw the error:

/bin/bash: opt/ros/melodic/setup.bash: No such file or directory

Works:

 => [stage-2 18/21] RUN ["/bin/bash", "-c", "source /opt/ros/melodic/setup.bash"]                                  0.5s
 => [stage-2 19/21] [...]

You might also put the commands you want to execute in a single bash script and run that bash script in the Dockerfile (though I would rather put the bash commands in the Dockerfile as well, just my opinion):

#!/bin/bash
set -e

source /opt/ros/melodic/setup.bash

---

PS: You can also put many bash commands in a row:

RUN ["/bin/bash", "-c", "source /opt/ros/melodic/setup.bash && MY_BASH_COMMAND && MY_BASH_COMMAND"]

or same with

RUN ["/bin/bash", "-c", "source /opt/ros/melodic/setup.bash;MY_BASH_COMMAND;MY_BASH_COMMAND"]

or in many lines with

RUN /bin/bash -c 'source /opt/ros/melodic/setup.bash &&\
    cd /MY_PROJECT &&\
    catkin_make -j8;\
    echo "source /MY_PROJECT/devel/setup.bash" >> ~/.bashrc'

or same with

RUN /bin/bash -c 'source /opt/ros/melodic/setup.bash;\
    cd /MY_PROJECT;\
    catkin_make -j8;\
    echo "source /MY_PROJECT/devel/setup.bash" >> ~/.bashrc'

Mind that when using RUN ["/bin/bash", "-c", "..."] with this [] frame, this works only in a one-liner. At least I could not (!) get it to run with:

RUN ["/bin/bash", "-c", "source /opt/ros/melodic/setup.bash && \
    cd /MY_PROJECT && \
    catkin_make -j8"]

nor with

RUN ["/bin/bash", "-c", "source /opt/ros/melodic/setup.bash && 
    cd /MY_PROJECT && 
    catkin_make -j8"]

nor with

RUN ["/bin/bash", "-c", "source /opt/ros/melodic/setup.bash; \
    cd /MY_PROJECT; \
    catkin_make -j8"]

nor with

RUN ["/bin/bash", "-c", "source /opt/ros/melodic/setup.bash;
    cd /MY_PROJECT;
    catkin_make -j8"]

The error was always like:

executor failed running ... exit code: 127

---

PS2: You can also add the source command to the .bashrc (the "run commands" at the start of the bash) so that this is loaded at every start of the bash:

RUN ["/bin/bash", "-c", "echo 'source /MY_PROJECT/devel/setup.bash' >> ~/.bashrc"]

or

RUN /bin/bash -c 'echo "source /MY_PROJECT/devel/setup.bash" >> ~/.bashrc'

Comments

[stark]

source is a bash built-in, not a command.

[questionto42standswithUkraine]

@stark It is just the example here. You would have the same problem with any other real command that is not built-in. If it is built-in or not does not change the idea here, and I wonder how I should name it then.