(command.CommandList
  children: [
    (C {<_Dbg_help_add>} {<tty>} 
      {
        (SQ <'tty\n'> <'\n'> 
          <'Set the output device for debugger output. Use "&1" if you want debugger\n'> <'output to go to STDOUT.\n'>
        )
      }
    )
    (command.ShFunction
      name: _Dbg_do_tty
      body: 
        (BraceGroup
          children: [
            (C {<typeset>} {<-i>} {<Id.Lit_VarLike 'rc='> <0>})
            (command.If
              arms: [
                (if_arm
                  cond: 
                    (condition.Shell
                      commands: [
                        (command.Sentence
                          child: 
                            (command.DParen
                              child: 
                                (arith_expr.Binary
                                  op_id: Id.Arith_Less
                                  left: {($ Id.VSub_Pound '$#')}
                                  right: {<Id.Lit_Digits 1>}
                                )
                            )
                          terminator: <Id.Op_Semi _>
                        )
                      ]
                    )
                  action: [
                    (C {<_Dbg_errmsg>} 
                      {(DQ <'Argument required (terminal name for running target process).'>)}
                    )
                    (command.ControlFlow
                      token: <Id.ControlFlow_Return return>
                      arg_word: {<1>}
                    )
                  ]
                  spids: [89 104]
                )
              ]
            )
            (C {<typeset>} {<Id.Lit_VarLike 'tty='> ($ Id.VSub_Number '$1')})
            (command.If
              arms: [
                (if_arm
                  cond: 
                    (condition.Shell
                      commands: [
                        (command.Sentence
                          child: (C {<_Dbg_check_tty>} {($ Id.VSub_DollarName '$tty')})
                          terminator: <Id.Op_Semi _>
                        )
                      ]
                    )
                  action: [
                    (command.ShAssignment
                      pairs: [
                        (assign_pair
                          lhs: (sh_lhs_expr.Name name:_Dbg_tty)
                          op: assign_op.Equal
                          rhs: {($ Id.VSub_DollarName '$tty')}
                          spids: [140]
                        )
                      ]
                    )
                    (command.ShAssignment
                      pairs: [
                        (assign_pair
                          lhs: (sh_lhs_expr.Name name:_Dbg_prompt_output)
                          op: assign_op.Equal
                          rhs: {($ Id.VSub_DollarName '$_Dbg_tty')}
                          spids: [144]
                        )
                      ]
                    )
                    (C {<_Dbg_msg>} 
                      {(DQ <'Debugger output set to go to '> ($ Id.VSub_DollarName '$_Dbg_tty'))}
                    )
                  ]
                  spids: [128 136]
                )
              ]
            )
            (command.ControlFlow token:<Id.ControlFlow_Return return> arg_word:{<0>})
          ]
        )
    )
  ]
)