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I tried very hard to create the feature I was looking for without changing the source, but it just wasn't possible. I went through 3 or 4 prototypes, and event

I tried very hard to create the feature I was looking for without changing the source, but it just wasn't possible. I went through 3 or 4 prototypes, and eventually decided to just change bash itself (which was a good call in hindsight). I've had to make a few more change since too. The source patch is located at ~/.fop/patched-executables/bash-4.3.30-post-patch-call-python-hook.patch is has been applied after the LFS bash patch. This patch is extremely sloppy and breaks certain things, but it does what I need for now. The way it works for bash commands is before handing a line of input off to be processed, it calls an external python hook which decides whether that line of input should be ignored or not, gives the hook a change to perform it's own custom behaviour (such as print an error message).

mst 10y ago
Ah, I was thinking about "let it fail with the normal error message, and then print an explanation" - that way people learn to recognise the real error too for when they take the training wheels off. (I checked, even malformed lines like '|foo' go into the history)
- robertelder 10y ago
  Yeah, there are a few situations where it's a difficult call between getting them used to the 'real' environment vs holding their hand and telling them "bash: syntax error near unexpected token `|'". If I end up modifying it too much, then they start learning an alternate thing that isn't portable knowledge, but in this case I think it should be OK. I would make sense to possibly have a graduated progression where you expose them more and more to the real horrors of using the command line. I guess I'll see how it evolves. Another couple reasons I patched bash: Being able to detect when users use tab completion and using the up key to check history. Those are 2 massive productivity enhancements, and I wanted to created modules where I can verify that they used these.

mst 10y ago

Ah, I was thinking about "let it fail with the normal error message, and then print an explanation" - that way people learn to recognise the real error too for when they take the training wheels off. (I checked, even malformed lines like '|foo' go into the history)

robertelder 10y ago
Yeah, there are a few situations where it's a difficult call between getting them used to the 'real' environment vs holding their hand and telling them "bash: syntax error near unexpected token `|'". If I end up modifying it too much, then they start learning an alternate thing that isn't portable knowledge, but in this case I think it should be OK. I would make sense to possibly have a graduated progression where you expose them more and more to the real horrors of using the command line. I guess I'll see how it evolves. Another couple reasons I patched bash: Being able to detect when users use tab completion and using the up key to check history. Those are 2 massive productivity enhancements, and I wanted to created modules where I can verify that they used these.