curl -s https://raw.githubusercontent.com/apptainer/apptainer/main/tools/install-unprivileged.sh | bash -s - /home/happy_ling/apptainer

$ apptainer  
Usage:  
 apptainer [global options...] <command>  
  
Available Commands:  
 build       Build an Apptainer image  
 cache       Manage the local cache  
 capability  Manage Linux capabilities for users and groups  
 checkpoint  Manage container checkpoint state (experimental)  
 completion  Generate the autocompletion script for the specified shell  
 config      Manage various apptainer configuration (root user only)  
 delete      Deletes requested image from the library  
 exec        Run a command within a container  
 inspect     Show metadata for an image  
 instance    Manage containers running as services  
 key         Manage OpenPGP keys  
 oci         Manage OCI containers  
 overlay     Manage an EXT3 writable overlay image  
 plugin      Manage Apptainer plugins  
 pull        Pull an image from a URI  
 push        Upload image to the provided URI  
 remote      Manage apptainer remote endpoints, keyservers and OCI/Docker  
registry credentials  
 run         Run the user-defined default command within a container  
 run-help    Show the user-defined help for an image  
 search      Search a Container Library for images  
 shell       Run a shell within a container  
 sif         Manipulate Singularity Image Format (SIF) images  
 sign        Add digital signature(s) to an image  
 test        Run the user-defined tests within a container  
 verify      Verify digital signature(s) within an image  
 version     Show the version for Apptainer  
  
Run 'apptainer --help' for more detailed usage information.