Support for taking stdin or using termshot as a pipe

[5HT2]

I'm not too sure if this is possible, though given the following sequence of commands, I think it should be possible code-wise?

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Naturally, if I attempt to use - as the command or simply nothing, it just errors, though, given the fact it's still able to take stdin as a command, and correctly produce a screenshot, when provided with any valid executable, seems to point to it just being an error handling thing.

If you can point me to where in the code this kind of thing is handled, I'm more than happy to impl it myself and open a pull request :)