

A proof that Unix utility "sed" is Turing complete - Anon84
http://www.catonmat.net/blog/proof-that-sed-is-turing-complete/

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politician
There isn't much here except a sed program and a printout demonstrating 151
being incremented once.

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pkrumins
I improved the article a little. Take a look now.

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politician
Thanks, I found the link to the busy beaver problem, and go my money's worth.
But seriously, that was an interesting post.

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rollypolly
Can we also prove that awk is Turing complete this way?

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pkrumins
That's not the point.

Many people are surprised when they hear that sed is Turing complete. How come
a text filtering program is Turing complete they ask? Turns out sed is like a
small assembly language that has a comparison operation, a branching operation
and a temporary buffer. If you translate a problem into a textual
representation then these operations are enough to make sed Turing complete!

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yzhengyu
_Shrug_ Even more people are surprised that Excel is Turing complete.

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wladimir
That's not entirely a fair comparison as Excel contains a complete VB
environment.

