It's explained under the July 2025 heading with link to the blog post where it was first shared.

The key bit is right under that though. Ralph is literally just this:

    while :; do cat PROMPT.md | npx --yes @sourcegraph/amp ; done

Surely that would be better written as

    cat PROMPT.md | cat | npx --yes @sourcegraph/amp

You've removed the loop. This pipeline executes once and then halts.

Aside from losing the loop (the whole point of the command), why the double `cat`?

I think it was an attempt at a useless use of cat joke (cat isn't needed at all here, but IMHO helps readability).

Thanks!

This is meaningless without knowing the contents of PROMPT.md. The blog post hides the contents of PROMPT.md in a second subscriber-only post (I don't know if the post's 36 minute video explains anything - 33% in it still hasn't).

https://github.com/repomirrorhq/repomirror/blob/main/repomir... (discussed in https://news.ycombinator.com/item?id=45005434) provides a bit more detail, and prompts, but only seems to use the method for porting existing software.

there are hundreds of useful resources, including many linked in the article itself