functioning docker mod in Duplicati

duplicati:
    image: linuxserver/duplicati:v2.0.5.1-2.0.5.1_beta_2020-01-18-ls79
    container_name: duplicati
....
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$ docker exec -it -u abc duplicati /bin/bash
abc@f6231628d9c4:/$ docker

Usage:  docker [OPTIONS] COMMAND

A self-sufficient runtime for containers
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