(command.CommandList
  children: [
    (C {<'/bin/echo'>} {<-n>} {(DQ <'User account: '>)})
    (C {<read>} {<account>})
    (command.If
      arms: [
        (if_arm
          cond: 
            (condition.Shell
              commands: [
                (command.Sentence
                  child: 
                    (C {<Id.Lit_LBracket '['>} {<-z>} {($ Id.VSub_DollarName '$account')} 
                      {<Id.Lit_RBracket ']'>}
                    )
                  terminator: <Id.Op_Semi _>
                )
              ]
            )
          action: [
            (command.Sentence
              child: (command.ControlFlow token:<Id.ControlFlow_Exit exit> arg_word:{<0>})
              terminator: <Id.Op_Semi _>
            )
          ]
          spids: [21 33]
        )
      ]
    )
    (command.If
      arms: [
        (if_arm
          cond: 
            (condition.Shell
              commands: [
                (command.Sentence
                  child: 
                    (C {<Id.Lit_LBracket '['>} {<-z>} {(DQ ($ Id.VSub_Number '$1'))} 
                      {<Id.Lit_RBracket ']'>}
                    )
                  terminator: <Id.Op_Semi _>
                )
              ]
            )
          action: [
            (C {<'/bin/echo'>} {<-n>} {(DQ <'Remote host: '>)})
            (C {<read>} {<host>})
            (command.If
              arms: [
                (if_arm
                  cond: 
                    (condition.Shell
                      commands: [
                        (command.Sentence
                          child: 
                            (C {<Id.Lit_LBracket '['>} {<-z>} {($ Id.VSub_DollarName '$host')} 
                              {<Id.Lit_RBracket ']'>}
                            )
                          terminator: <Id.Op_Semi _>
                        )
                      ]
                    )
                  action: [(command.ControlFlow token:<Id.ControlFlow_Exit exit> arg_word:{<0>})]
                  spids: [78 90]
                )
              ]
            )
          ]
          spids: [47 61]
        )
      ]
      else_action: [
        (command.ShAssignment
          pairs: [
            (assign_pair
              lhs: (sh_lhs_expr.Name name:host)
              op: assign_op.Equal
              rhs: {($ Id.VSub_Number '$1')}
              spids: [103]
            )
          ]
        )
      ]
    )
    (C {<exec>} {<sftp>} {<-C>} 
      {($ Id.VSub_DollarName '$account') <Id.Lit_At '@'> ($ Id.VSub_DollarName '$host')}
    )
  ]
)