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Comment by psd1 | Hacker News Reader

No gnu tool can balance brackets, afaics. So you can't do everything in sed. And sed is, by design, useless for matching text that spans lines, so good luck picking out paragraphs with it.

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Sorry I meant to write “if you can do it in sed you can do it in anything” thereby implying it is a subset of the more generally available flavours. The issue at hand however is that there isn’t much in the way of standardisation but 95% of sed should work across all of them. Of course you should get more into the specifics of whatever your solution space supports.

I am pretty sure even pure Awk can do it; or am I mistaken? I thought there was an even more sophisticated example in the Awk book.

Edit: oh, you mean via regex engines available in GNU tools; I am dumb. Hmm... is there no GNU extension with PCRE?

"Sed" is the name of a specific tool. It is not defined by the GNU tools, but has existed in some form since 1974, well before Perl. GNU sed and POSIX sed both support BRE and EREs, but not PCREs.

Maybe there's some other implementation of sed that supports PCREs but that would really be an extension of that implementation of sed rather than a property of sed.

And maybe there's some GNU tool that uses PCREs, but that GNU tool would not be GNU sed, so it would not be a relevant property.

Anyway, they probably should have said BREs or EREs rather than "sed"...

Nope. Gnu regex tools also do not support lookahead or alternation. Lookahead is really useful.

It's a problem for Linux that it can't move on. The cold dead hand of gnu is firmly around the community's neck.

> the cold dead hand …

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