Can't pipe redis-cli psubscribe into another command?

[Roger Lipscombe]

If I run "redis-cli LRANGE mylist 0 -1 | cat", I can see the output.
On the other hand, if I run "redis-cli PSUBSCRIBE pattern | cat",
nothing appears.

Is this a bug? Am I doing something wrong?

Note that I'm only using "cat" as an example. I'm actually trying to
use "| grep '^{' | jq".

[Jan-Erik Rediger]

redis-cli output is buffered. It works in the case of LRANGE because
once that is finished, it quits and thus flushes output buffers.

Use the famous Linux utility `stdbuf` to make it line-buffered and
achieve what you want:

stdbuf -oL redis-cli psubscribe pattern | grep '^{' | jq ...

You can make it completely unbuffered using `stdbuf -o0` instead.

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[Roger Lipscombe]

It turns out that you need to apply the buffering options to grep *as well*:

stdbuf -oL redis-cli --raw psubscribe pattern | stdbuf -oL grep "^{" | jq

https://github.com/stedolan/jq/issues/477 talks about 'cut', but it's
the same problem.