[Newbies] CommandShell/OSPRocess primCreatePipe failing. How to debug?

In

ExternalPipe>> makePipe | t1 | *t1 := OSProcess accessor makePipeHandles.* t1 isNil ifTrue: [self error: 'cannot create OS pipe'] ifFalse: [self reader: (AttachableFileStream name: 'pipeReader' attachTo: (t1 at: 1) writable: false). self writer: (AttachableFileStream name: 'pipeWriter' attachTo: (t1 at: 2) writable: true)]

OSProcess accessor is a * 'a UnixOSProcessAccessor on pid 19790'*

Where *self makePipeHandles* returns and undefined object.

How should I think about this?

thnks

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