parallelization - wolframscript command line output from ParallelDo kernels contains lots of gibberish

I run this code:

ParallelDo[
  Print["Hi"];,

  {i,Range[2]}
  ]

And I get this:

Launching kernels...
StringForm[From `1`:, Parallel`Kernels`kernel[Parallel`Kernels`Private`bk[SubKernels`LocalKernels`localKernel[SubKernels`LocalKernels`Private`lk[LinkObject["C:\Program Files\Wolfram Research\Mathematica\12.0\WolframKernel" -noicon -subkernel -noinit -nopaclet -wstp, 93, 4], {"C:\Program Files\Wolfram Research\Mathematica\12.0\WolframKernel" -noicon -subkernel -noinit -nopaclet -wstp, SubKernels`LocalKernels`LowerPriority -> False}, SubKernels`LocalKernels`Private`speed$1005, SubKernels`LocalKernels`Private`preemptive$1005]], Parallel`Kernels`Private`id$1021, Parallel`Kernels`Private`name$1021], Parallel`Kernels`Private`ek[Parallel`Kernels`Private`nev$1022, Parallel`Kernels`Private`pb$1022, Parallel`Kernels`Private`rd$1022], Parallel`Kernels`Private`sk[Parallel`Kernels`Private`q$1023, Parallel`Kernels`Private`n0$1023, Parallel`Kernels`Private`n1$1023]]]
Hi

StringForm[From `1`:, Parallel`Kernels`kernel[Parallel`Kernels`Private`bk[SubKernels`LocalKernels`localKernel[SubKernels`LocalKernels`Private`lk[LinkObject["C:\Program Files\Wolfram Research\Mathematica\12.0\WolframKernel" -noicon -subkernel -noinit -nopaclet -wstp, 92, 3], {"C:\Program Files\Wolfram Research\Mathematica\12.0\WolframKernel" -noicon -subkernel -noinit -nopaclet -wstp, SubKernels`LocalKernels`LowerPriority -> False}, SubKernels`LocalKernels`Private`speed$1004, SubKernels`LocalKernels`Private`preemptive$1004]], Parallel`Kernels`Private`id$1017, Parallel`Kernels`Private`name$1017], Parallel`Kernels`Private`ek[Parallel`Kernels`Private`nev$1018, Parallel`Kernels`Private`pb$1018, Parallel`Kernels`Private`rd$1018], Parallel`Kernels`Private`sk[Parallel`Kernels`Private`q$1019, Parallel`Kernels`Private`n0$1019, Parallel`Kernels`Private`n1$1019]]]
Hi

This is especially disruptive because the middle line ("StringForm[...") wraps across and takes over most of my screen space. Reading the output becomes very difficult. Is there a way to hide the gibberish?

Answer

The underlying cause is that default output format is ScriptForm when using math -script or wolframscript.

To work around this issue, put the following at the beginning of your script:

SetOptions[$Output, FormatType -> OutputForm]

I did report this problem to Wolfram some months ago.