Squeak on Linux cannot read from `/dev/stdin`

[LinqLover]

(FileStream readOnlyFileNamed: '/dev/stdin') contents --> MultiByteFileStream(StandardFileStream)>>primGetPosition: failed (ec: nil)

$ squeak squeak/FreshTrunk.image --file /dev/stdin <<EOF
> 'From Squeak6.1rc2 of 2 August 2026 [latest update: #23945] on 2 August 2026 at 9:38:14 pm'!

!Object methodsFor: 'accessing' stamp: 'ct 8/2/2026 21:38'!
newselector
        ^self! !
EOF
MessageNotUnderstood: UndefinedObject>>contentsOfEntireFile

[LinqLover]

Same for file descriptors

$ squeak squeak/FreshTrunk.image --file <(cat <<EOF
'From Squeak6.1rc2 of 2 August 2026 [latest update: #23945] on 2 August 2026 at 9:38:14 pm'!

!Object methodsFor: 'accessing' stamp: 'ct 8/2/2026 21:38'!
newselector
        ^self! !
EOF
)
MessageNotUnderstood: UndefinedObject>>contentsOfEntireFile

[dtlewis290]

The root cause of this and many related problems is that our file streams all inherit from PositionableStream, but pipes and stdio streams (and socket streams etc) are not positionable. We do not have a proper representation of non-positionable I/O streams.

If you have OSProcess/CommandShell loaded, take a look at AttachableFileStream. This is a complete kludge (I can say the because I wrote it) but it gives an idea of the workarounds needed make a few simple things work when a file stream is attached to a non-positionable stream.