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    # fork and forkwait
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  | 2 | 
  
    
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    shopt --set oil:upgrade
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    shopt --unset errexit
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    fork
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    echo status=$?
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    fork extra
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    echo status=$?
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    fork extra {
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      echo hi
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    }
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    echo status=$?
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    #
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    forkwait
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    echo status=$?
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    forkwait extra
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    echo status=$?
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    forkwait extra {
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      echo hi
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    }
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    echo status=$?
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    ## STDOUT:
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    status=2
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    status=2
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    status=2
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  | 35 | 
  
    status=2
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    status=2
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    status=2
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  | 38 | 
  
    ## END
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  | 39 | 
  
    
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    shopt --set oil:upgrade
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  | 42 | 
  
    shopt --unset errexit
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  | 43 | 
  
    
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  | 44 | 
  
    old=$PWD
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  | 45 | 
  
    
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    forkwait {
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      cd /
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      echo hi
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      exit 42
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    }
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    echo status=$?
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    if test "$old" = "$PWD"; then
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  | 53 | 
  
      echo ok
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    fi
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  | 55 | 
  
    ## STDOUT:
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  | 56 | 
  
    hi
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  | 57 | 
  
    status=42
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  | 58 | 
  
    ok
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  | 59 | 
  
    ## END
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  | 60 | 
  
    
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  | 61 | 
  
    
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    shopt --set oil:upgrade
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  | 63 | 
  
    shopt --unset errexit
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  | 64 | 
  
    
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  | 65 | 
  
    old=$PWD
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  | 66 | 
  
    
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  | 67 | 
  
    fork {
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      cd /
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  | 69 | 
  
      echo hi
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      sleep 0.01 
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      exit 42
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    }
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    #echo status=$?  race condition
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  | 74 | 
  
    
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    wait -n
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  | 76 | 
  
    echo status=$?
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  | 77 | 
  
    
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  | 78 | 
  
    if test "$old" = "$PWD"; then
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  | 79 | 
  
      echo ok
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    fi
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  | 81 | 
  
    ## STDOUT:
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  | 82 | 
  
    hi
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  | 83 | 
  
    status=42
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  | 84 | 
  
    ok
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  | 85 | 
  
    ## END
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