A few years ago I added the %help section to the singularity recipe. The idea was that if you wrote this section in your Singularity recipe, the user could ask your container for help!
$ singularity help helpme.sif
Oh, hi there! This is the help section. Here is how to run the container:
singularity run <container>
Here is how to shell into the container:
singularity shell <container>
Here is how to execute a custom command
singularity exec <container> ls /
But there is one problem here, we are still relying on the user to type that command in the first place! This is a great use case for message of the day (motd) - we can show this same help script when the user shells into the container! Here is what the Singularity recipe looks like:
$ singularity shell helpme.sif
Singularity: Invoking an interactive shell within container...
Oh, hi there! This is the help section. Here is how to run the container:
singularity run <container>
Here is how to shell into the container:
singularity shell <container>
Here is how to execute a custom command
singularity exec <container> ls /
Singularity helpme.sif:~/Documents/Dropbox/Code/singularity/motd/help> It would be more informative to have paths or other usage that a user shelling into the container might need. Or you could add dependencies for usage like mounting a particular directory, or setting an environment variable.