Bash autocomplete

• /etc/bash_completion.d/enter-docker:

  _dothis_completions()
  {
    if [ "${#COMP_WORDS[@]}" != "2" ]; then
      return
    fi
    # COMPREPLY=($(compgen -W "now tomorrow never" "${COMP_WORDS[1]}"))
    # keep the suggestions in a local variable
  
    local suggestions=($(compgen -W "$(docker ps --format ''| tr '\n' ' '| sed 's/ *$//')" -- "${COMP_WORDS[1]}"))
  
    if [ "${#suggestions[@]}" == "1" ]; then
      # if there's only one match, we remove the command literal
      # to proceed with the automatic completion of the number
      local number=$(echo ${suggestions[0]/%\ */})
      COMPREPLY=("$number")
    else
      # more than one suggestions resolved,
      # respond with the suggestions intact
      COMPREPLY=("${suggestions[@]}")
    fi
  }
  
  complete -F _dothis_completions enter-docker shenter-docker
  

• /usr/bin/enter-docker:

  #!/bin/bash
  docker exec -ti $1 bash
  

• Reference: Creating a bash completion script