(command.CommandList
  children: [
    (command.AndOr
      ops: [Id.Op_DPipe]
      children: [
        (C {<_userland>} {<GNU>})
        (command.ControlFlow token:<Id.ControlFlow_Return return> arg_word:{<1>})
      ]
    )
    (command.AndOr
      ops: [Id.Op_DAmp]
      children: [
        (command.ShFunction
          name: _ifupdown
          body: 
            (command.BraceGroup
              children: [
                (C {<local>} {<cur>} {<prev>} {<words>} {<cword>})
                (command.AndOr
                  ops: [Id.Op_DPipe]
                  children: [
                    (C {<_init_completion>})
                    (command.ControlFlow token:<Id.ControlFlow_Return return>)
                  ]
                )
                (command.If
                  arms: [
                    (if_arm
                      cond: [
                        (command.Sentence
                          child: 
                            (command.DBracket
                              expr: 
                                (bool_expr.Binary
                                  op_id: Id.BoolBinary_eq
                                  left: {($ Id.VSub_DollarName '$cword')}
                                  right: {<1>}
                                )
                            )
                          terminator: <Id.Op_Semi _>
                        )
                      ]
                      action: [
                        (C {<_configured_interfaces>})
                        (command.ShAssignment
                          pairs: [
                            (assign_pair
                              lhs: (sh_lhs_expr.Name name:COMPREPLY)
                              op: assign_op.Equal
                              rhs: 
                                {
                                  (sh_array_literal
                                    left: <Id.Op_LParen _>
                                    words: [
                                      {
                                        (command_sub
                                          left_token: <Id.Left_DollarParen '$('>
                                          command_list: 
                                            (command.CommandList
                                              children: [
                                                (C {<compgen>} {<-W>} {(SQ <'${COMPREPLY[@]}'>)} {<-->} 
                                                  {(DQ ($ Id.VSub_DollarName '$cur'))}
                                                )
                                              ]
                                            )
                                        )
                                      }
                                    ]
                                  )
                                }
                              spids: [60]
                            )
                          ]
                        )
                      ]
                      spids: [41 54]
                    )
                  ]
                )
                (command.ControlFlow
                  token: <Id.ControlFlow_Return return>
                  arg_word: {<0>}
                )
              ]
            )
        )
        (C {<complete>} {<-F>} {<_ifupdown>} {<ifup>} {<ifdown>} {<ifstatus>})
      ]
    )
  ]
)