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                  pairs: [
                    (AssignPair
                      left: <Id.Lit_VarLike 'filter_i='>
                      lhs: (sh_lhs_expr.Name left:<Id.Lit_VarLike 'filter_i='> name:filter_i)
                      op: assign_op.Equal
                      rhs: {(DQ ($ Id.VSub_DollarName filter_i) <' && '>)}
                    )
                  ]
                  redirects: []
                )
              ]
              ops: [<Id.Op_DAmp _>]
            )
            (command.ShAssignment
              left: <Id.Lit_VarLike 'filter_i='>
              pairs: [
                (AssignPair
                  left: <Id.Lit_VarLike 'filter_i='>
                  lhs: (sh_lhs_expr.Name left:<Id.Lit_VarLike 'filter_i='> name:filter_i)
                  op: assign_op.Equal
                  rhs: {(DQ (${ Id.VSub_Name filter_i) <'common_pid == '> ($ Id.VSub_DollarName pid))}
                )
              ]
              redirects: []
            )
            (command.AndOr
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                  expr: 
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                    )
                  right: <Id.Lit_DRightBracket ']]'>
                  redirects: []
                )
                (command.ShAssignment
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                  pairs: [
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                      left: <Id.Lit_VarLike 'filter='>
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                    )
                  ]
                  redirects: []
                )
              ]
              ops: [<Id.Op_DAmp _>]
            )
          ]
          spids: [1030 1040]
        )
      ]
      else_action: []
      fi_kw: <Id.KW_Fi fi>
      redirects: []
    )
    (command.If
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                              op_id: Id.Arith_DPipe
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                              right: ($ Id.Lit_ArithVarLike opt_device)
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                    )
                  terminator: <Id.Op_Semi _>
                )
              ]
            )
          then_kw: <Id.KW_Then then>
          action: [
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              if_kw: <Id.KW_If if>
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                                  redirects: [
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                                      op: <Id.Redir_Great '>'>
                                      loc: (redir_loc.Fd fd:1)
                                      arg: 
                                        {<'events/block/'> ($ Id.VSub_DollarName b_start) <'/filter'>}
                                    )
                                  ]
                                  do_fork: T
                                )
                              ]
                              ops: []
                            )
                            (command.Pipeline
                              negated: <Id.KW_Bang '!'>
                              children: [
                                (command.Simple
                                  blame_tok: <echo>
                                  more_env: []
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                                  redirects: [
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                                      op: <Id.Redir_Great '>'>
                                      loc: (redir_loc.Fd fd:1)
                                      arg: {<'events/block/block_rq_complete/filter'>}
                                    )
                                  ]
                                  do_fork: T
                                )
                              ]
                              ops: []
                            )
                          ]
                          ops: [<Id.Op_DPipe _>]
                        )
                      ]
                    )
                  then_kw: <Id.KW_Then then>
                  action: [
                    (command.Simple
                      blame_tok: <edie>
                      more_env: []
                      words: [{<edie>} {(DQ <'ERROR: setting -d or -t filter. Exiting.'>)}]
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                      do_fork: T
                    )
                  ]
                  spids: [1116 1149]
                )
              ]
              else_action: []
              fi_kw: <Id.KW_Fi fi>
              redirects: []
            )
          ]
          spids: [1095 1113]
        )
      ]
      else_action: []
      fi_kw: <Id.KW_Fi fi>
      redirects: []
    )
    (command.If
      if_kw: <Id.KW_If if>
      arms: [
        (IfArm
          keyword: <Id.KW_If if>
          cond: 
            (condition.Shell
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                    (command.AndOr
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                        (command.Pipeline
                          negated: <Id.KW_Bang '!'>
                          children: [
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                              blame_tok: <echo>
                              more_env: []
                              words: [{<echo>} {<1>}]
                              redirects: [
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                                  op: <Id.Redir_Great '>'>
                                  loc: (redir_loc.Fd fd:1)
                                  arg: {<'events/block/'> ($ Id.VSub_DollarName b_start) <'/enable'>}
                                )
                              ]
                              do_fork: T
                            )
                          ]
                          ops: []
                        )
                        (command.Pipeline
                          negated: <Id.KW_Bang '!'>
                          children: [
                            (command.Simple
                              blame_tok: <echo>
                              more_env: []
                              words: [{<echo>} {<1>}]
                              redirects: [
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                                  op: <Id.Redir_Great '>'>
                                  loc: (redir_loc.Fd fd:1)
                                  arg: {<'events/block/block_rq_complete/enable'>}
                                )
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                              do_fork: T
                            )
                          ]
                          ops: []
                        )
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                    )
                  terminator: <Id.Op_Semi _>
                )
              ]
            )
          then_kw: <Id.KW_Then then>
          action: [
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              blame_tok: <edie>
              more_env: []
              words: [{<edie>} {(DQ <'ERROR: enabling block I/O tracepoints. Exiting.'>)}]
              redirects: []
              do_fork: T
            )
          ]
          spids: [1163 1192]
        )
      ]
      else_action: []
      fi_kw: <Id.KW_Fi fi>
      redirects: []
    )
    (command.AndOr
      children: [
        (command.DParen
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          child: ($ Id.Lit_ArithVarLike opt_start)
          right: <Id.Op_DRightParen _>
          redirects: []
        )
        (command.Simple
          blame_tok: <printf>
          more_env: []
          words: [{<printf>} {(DQ <'%-15s '>)} {(DQ <STARTs>)}]
          redirects: []
          do_fork: T
        )
      ]
      ops: [<Id.Op_DAmp _>]
    )
    (command.AndOr
      children: [
        (command.DParen
          left: <Id.Op_DLeftParen _>
          child: ($ Id.Lit_ArithVarLike opt_end)
          right: <Id.Op_DRightParen _>
          redirects: []
        )
        (command.Simple
          blame_tok: <printf>
          more_env: []
          words: [{<printf>} {(DQ <'%-15s '>)} {(DQ <ENDs>)}]
          redirects: []
          do_fork: T
        )
      ]
      ops: [<Id.Op_DAmp _>]
    )
    (command.Simple
      blame_tok: <printf>
      more_env: []
      words: [
        {<printf>}
        {(DQ <'%-12.12s %-6s %-4s %-8s %-12s %-6s %8s'> <Id.Lit_BadBackslash '\\'> <n>)}
        {(DQ <COMM>)}
        {(DQ <PID>)}
        {(DQ <TYPE>)}
        {(DQ <DEV>)}
        {(DQ <BLOCK>)}
        {(DQ <BYTES>)}
        {(DQ <LATms>)}
      ]
      redirects: []
      do_fork: T
    )
    (command.ShAssignment
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      pairs: [
        (AssignPair
          left: <Id.Lit_VarLike 'offset='>
          lhs: (sh_lhs_expr.Name left:<Id.Lit_VarLike 'offset='> name:offset)
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          rhs: 
            {
              (CommandSub
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                child: 
                  (command.Simple
                    blame_tok: <Id.VSub_DollarName '$awk'>
                    more_env: []
                    words: [
                      {($ Id.VSub_DollarName awk)}
                      {
                        (SQ <'BEGIN { o = 0; }\n'> 
                          <'\t$1 == "#" && $2 ~ /TASK/ && NF == 6 { o = 1; }\n'> <'\t$2 ~ /TASK/ { print o; exit }'>
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                      }
                      {<trace>}
                    ]
                    redirects: []
                    do_fork: T
                  )
                right: <Id.Eof_RParen _>
              )
            }
        )
      ]
      redirects: []
    )
    (command.Simple
      blame_tok: <warn>
      more_env: []
      words: [{<warn>} {(DQ <'echo > trace'>)}]
      redirects: []
      do_fork: T
    )
    (command.Pipeline
      children: [
        (command.Subshell
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          child: 
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              arms: [
                (IfArm
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                  cond: 
                    (condition.Shell
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                              right: <Id.Op_DRightParen _>
                              redirects: []
                            )
                          terminator: <Id.Op_Semi _>
                        )
                      ]
                    )
                  then_kw: <Id.KW_Then then>
                  action: [
                    (command.Simple
                      blame_tok: <sleep>
                      more_env: []
                      words: [{<sleep>} {($ Id.VSub_DollarName duration)}]
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                      do_fork: T
                    )
                    (command.Simple
                      blame_tok: <cat>
                      more_env: []
                      words: [{<cat>} {<trace>}]
                      redirects: []
                      do_fork: T
                    )
                  ]
                  spids: [1326 1336]
                )
              ]
              else_kw: <Id.KW_Else else>
              else_action: [
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                  more_env: []
                  words: [{<cat>} {<trace_pipe>}]
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              fi_kw: <Id.KW_Fi fi>
              redirects: []
            )
          right: <Id.Right_Subshell _>
          redirects: []
        )
        (command.Simple
          blame_tok: <Id.VSub_DollarName '$awk'>
          more_env: []
          words: [
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            {<-v>}
            {<Id.Lit_VarLike 'o='> ($ Id.VSub_DollarName offset)}
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            {<-v>}
            {<Id.Lit_VarLike 'name='> ($ Id.VSub_DollarName name)}
            {<-v>}
            {<Id.Lit_VarLike 'opt_duration='> ($ Id.VSub_DollarName opt_duration)}
            {<-v>}
            {<Id.Lit_VarLike 'opt_start='> ($ Id.VSub_DollarName opt_start)}
            {<-v>}
            {<Id.Lit_VarLike 'opt_end='> ($ Id.VSub_DollarName opt_end)}
            {<-v>}
            {<Id.Lit_VarLike 'b_start='> ($ Id.VSub_DollarName b_start)}
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                <'\t\ttime = $(3+o); sub(":", "", time)\n'> <'\t\tdev = $(5+o)\n'> <'\t}\n'> <'\n'> <'\t# block I/O request\n'> <'\t$1 != "#" && $0 ~ b_start {\n'> 
                <'\t\tif (opt_name && match(comm, name) == 0)\n'> <'\t\t\tnext\n'> <'\t\t#\n'> <'\t\t# example: (fields1..4+o) 202,1 W 0 () 12862264 + 8 [tar]\n'> 
                <'\t\t# The cmd field "()" might contain multiple words (hex),\n'> <'\t\t# hence stepping from the right (NF-3).\n'> <'\t\t#\n'> <'\t\tloc = $(NF-3)\n'> 
                <'\t\tstarts[dev, loc] = time\n'> <'\t\tcomms[dev, loc] = comm\n'> <'\t\tpids[dev, loc] = pid\n'> <'\t\tnext\n'> <'\t}\n'> <'\n'> 
                <'\t# block I/O completion\n'> <'\t$1 != "#" && $0 ~ /rq_complete/ {\n'> <'\t\t#\n'> 
                <'\t\t# example: (fields1..4+o) 202,1 W () 12862256 + 8 [0]\n'> <'\t\t#\n'> <'\t\tdir = $(6+o)\n'> <'\t\tloc = $(NF-3)\n'> <'\t\tnsec = $(NF-1)\n'> <'\n'> 
                <'\t\tif (starts[dev, loc] > 0) {\n'> <'\t\t\tlatency = sprintf("%.2f",\n'> <'\t\t\t    1000 * (time - starts[dev, loc]))\n'> 
                <'\t\t\tcomm = comms[dev, loc]\n'> <'\t\t\tpid = pids[dev, loc]\n'> <'\n'> <'\t\t\tif (opt_start)\n'> 
                <'\t\t\t\tprintf "%-15s ", starts[dev, loc]\n'> <'\t\t\tif (opt_end)\n'> <'\t\t\t\tprintf "%-15s ", time\n'> 
                <'\t\t\tprintf "%-12.12s %-6s %-4s %-8s %-12s %-6s %8s\\n",\n'> <'\t\t\t    comm, pid, dir, dev, loc, nsec * 512, latency\n'> <'\t\t\tif (!opt_duration)\n'> 
                <'\t\t\t\tfflush()\n'> <'\n'> <'\t\t\tdelete starts[dev, loc]\n'> <'\t\t\tdelete comms[dev, loc]\n'> 
                <'\t\t\tdelete pids[dev, loc]\n'> <'\t\t}\n'> <'\t\tnext\n'> <'\t}\n'> <'\n'> 
                <'\t$0 ~ /LOST.*EVENTS/ { print "WARNING: " $0 > "/dev/stderr" }\n'>
              )
            }
          ]
          redirects: []
          do_fork: T
        )
      ]
      ops: [<Id.Op_Pipe _>]
    )
    (command.Simple blame_tok:<end> more_env:[] words:[{<end>}] redirects:[] do_fork:T)
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)