By default, a Singularity image only have access to a limited set of paths once created. Without any special configurations, your $HOME (~/) and /tmp/ (among a few other system-specific locations) are accessible from within a container. However, this will not automatically bind your data/ or scratch/ directories, and thus they will not be accessible. The easiest method to gain access to these directories is to use the bind functionality to mount these volumes to the container on runtime.
Binding is achieved using the --bind or -B argument followed by the <hostPath>:<containerPath>
$ singularity shell -B /oscar/home/$USER,/oscar/scratch/$USER,/oscar/data <yourContainer.simg>This will bind /oscar/data``, /oscar/scratch and /oscar/home from OSCAR's GPFS to /oscar/data and /oscar/scratch within the container, respectively. Doing this will allow any existing links you have to your data and scratch directories to function properly.
An alternative approach is to use the SINGULARITY_BINDPATH environment variable which is used as a list of additional bind paths that will be included in any singularity commands you execute, including run and shell. Using the environment variable instead of the command line argument, this would be:
export SINGULARITY_BINDPATH="/oscar/home/$USER,/oscar/scratch/$USER,/oscar/data"
singularity run <yourContainer.simg>You can add various additional command options to configure the read/write permissions for these mounted volumes. For more information regarding file or path binds, please see the official Mounting and binding documentation from Singularity.