(command.CommandList
  children: [
    (command.ShAssignment
      pairs: [
        (assign_pair
          lhs: (sh_lhs_expr.Name name:tid)
          op: assign_op.Equal
          rhs: {(DQ <'yes pipe head'>)}
          spids: [7]
        )
      ]
    )
    (command.ForEach
      iter_name: p
      iter_words: [{(${ Id.VSub_Name SSH_PROTOCOLS)}]
      do_arg_iter: F
      body: 
        (command.DoGroup
          children: [
            (command.ShAssignment
              pairs: [
                (assign_pair
                  lhs: (sh_lhs_expr.Name name:lines)
                  op: assign_op.Equal
                  rhs: 
                    {
                      (command_sub
                        left_token: <Id.Left_Backtick '`'>
                        child: 
                          (command.Pipeline
                            children: [
                              (C {(${ Id.VSub_Name SSH)} {<-> ($ Id.VSub_DollarName '$p')} {<-F>} 
                                {($ Id.VSub_DollarName '$OBJ') <'/ssh_proxy'>} {<thishost>} {(SQ <'sh -c "while true;do echo yes;done | _POSIX2_VERSION=199209 head -2000"'>)}
                              )
                              (command.Subshell
                                child: 
                                  (command.CommandList
                                    children: [
                                      (command.Sentence
                                        child: (C {<sleep>} {<3>})
                                        terminator: <Id.Op_Semi _>
                                      )
                                      (C {<wc>} {<-l>})
                                    ]
                                  )
                              )
                            ]
                            negated: F
                          )
                      )
                    }
                  spids: [27]
                )
              ]
            )
            (command.If
              arms: [
                (if_arm
                  cond: 
                    (condition.Shell
                      commands: [
                        (command.Sentence
                          child: 
                            (C {<Id.Lit_LBracket '['>} {($ Id.VSub_QMark '$?')} {<-ne>} {<0>} 
                              {<Id.Lit_RBracket ']'>}
                            )
                          terminator: <Id.Op_Semi _>
                        )
                      ]
                    )
                  action: [
                    (C {<fail>} {(DQ <'yes|head test failed'>)})
                    (command.Sentence
                      child: (C {<lines>} {<Id.Lit_Equals '='>} {<0>})
                      terminator: <Id.Op_Semi _>
                    )
                  ]
                  spids: [65 78]
                )
              ]
            )
            (command.If
              arms: [
                (if_arm
                  cond: 
                    (condition.Shell
                      commands: [
                        (command.Sentence
                          child: 
                            (C {<Id.Lit_LBracket '['>} {($ Id.VSub_DollarName '$lines')} {<-ne>} {<2000>} 
                              {<Id.Lit_RBracket ']'>}
                            )
                          terminator: <Id.Op_Semi _>
                        )
                      ]
                    )
                  action: [
                    (C {<fail>} 
                      {
                        (DQ <'yes|head returns '> ($ Id.VSub_DollarName '$lines') 
                          <' lines instead of 2000'>
                        )
                      }
                    )
                  ]
                  spids: [99 112]
                )
              ]
            )
          ]
        )
    )
  ]
)