complete -c os -f
complete -c os -l add  -d "create a new container"
complete -c os -l add-from  -d "create a new image"
complete -c os -l del  -d "Remove a container"
complete -c os -l use  -d "Enter inside the container"
complete -c os -l run -d "Run a command inside the container"
complete -c os -l list  -d "List all containers"
complete -c os -l stop  -d "List all containers"