Mastodawn

Amin, minor deity of the legume realm Feb 4

@rl_dane

Oh, didn't know about -c. I usually just pipe to wc -l I guess.

-c, -l, -h, -H, and -q are my favorite #grep flags. :D

Huh, that almost became a [Marcel Duchamp] reference. 😅

Marcel Duchamp - Wikipedia

Amin, minor deity of the legume realm Feb 4

@rl_dane

I just use -v and -E

sotolf Feb 4

@amin @rl_dane you guys use flags?... :p

thedoctor Feb 4

@amin @rl_dane @sotolf You guys still use grep instead of ripgrep. Tst

@thedoctor @amin @sotolf

...and bash instead of zsh
...and grep/awk/sed instead of jq
...and firefox instead of chrome
...and the fediverse instead of facebook

Face it... I'm an unpopular-opinion neckbeard level boss. XD

cc: @mirabilos

thedoctor Feb 5

@rl_dane Those are so not comparable!

@amin @sotolf @mirabilos

sotolf Feb 5

@thedoctor @rl_dane @amin @mirabilos At least bash and zsh is comparable to grep ripgrep, as zsh is just a strictly better bash ;)

Amin, minor deity of the legume realm Feb 5

@sotolf @thedoctor @rl_dane @mirabilos

Mm, not really though? ripgrep is meant for bulk grepping of files

sotolf Feb 5

@amin @thedoctor @rl_dane @mirabilos I think I had it installed, I just never remembered to use it :p

Amin, minor deity of the legume realm Feb 5

@sotolf @thedoctor @rl_dane @mirabilos

I mostly just use it to run rg TODO and see all the spots in a codebase I marked as still needing work.

@amin @sotolf @thedoctor @mirabilos

Why is ripgrep better than just grep -R?

@kabel42 @amin @sotolf @thedoctor @mirabilos

@rl_dane @amin @sotolf @thedoctor @mirabilos it's somehow a lot faster if you want to grep a few GiB of code, like 15 minutes to 30 seconds

Interesting! I wonder what kind of algorithmic optimizations (as opposed to compiler optimizations) they're using to do that, and if regular (GNU/BSD) grep could do the same.

Because I'll wear clown shoes and a tutu before changing to a "rewrite the world in rust!" utility 😂

@rl_dane @amin @sotolf @thedoctor @mirabilos From what little i have read, some assumptions about what you are greping and different defaults. Doing the same in existing grep would probably break compatibility.

@mirabilos @kabel42 @amin @sotolf @thedoctor

@kabel42 @rl_dane @amin @sotolf @thedoctor eww, it’s not even a drop-in then…

(For not-a-drop-in, I found pcregrep interesting. Sadly, Debian recently dropped it, but in the versions which don’t have pcregrep any more, you can use grep -P for many use cases. pcre2grep is not a drop-in for pcregrep either…)

I was a total PCRE stan in the olden days, but I've steered more towards regular extended regexp for compatibility. I do miss \d, \w and \s, though. [[:space:]] feels so clumsy to type and use several times in a regex, I'll sometimes put a sp="[[:space:]]" line at the start of a script, and you'll see several invocations of "${sp}" in my regex strings.

But again... compatibility. ;)

Is there a big difference between (GNU) grep -P and pcregrep? I hadn't heard of that utility before.

@amin @kabel42 @rl_dane @sotolf @thedoctor I never used \d and the likes, always felt them much too complicated. I almost never use POSIX character classes (besides the BSD [[:<:]] and [[:>:]]), rather I just hit [ tab space ] quickly.

GNU grep -P does a PCRE grep, it doesn’t support all of the extra flags of pcregrep though, and before the version in IIRC trixie was very broken.

is [[:<:]] and [[:>:]] the same as \< and \>?

@rl_dane @amin @kabel42 @sotolf @thedoctor obviously not, because it’s written differently ;)

re_format(7) knows:

     There are two special cases** of bracket expressions: the bracket expres-
     sions '[[:<:]]' and '[[:>:]]' match the null string at the beginning and
     end of a word, respectively. A word is defined as a sequence of charac-
     ters starting and ending with a word character which is neither preceded
     nor followed by word characters. A word character is an alnum character
     (as defined by ctype(3)) or an underscore. This is an extension, compati-
     ble with but not specified by POSIX, and should be used with caution in
     software intended to be portable to other systems.


(as for the mark:)
     POSIX leaves some aspects of RE syntax and semantics open; '**' marks de-
     cisions on these aspects that may not be fully portable to other POSIX
     implementations.

The definition for \< / \> differs between less, perlre, pcre, … I believe, but they all are somewhat simiar.

@rl_dane @amin @kabel42 @sotolf @thedoctor perlre(1) actually has…

     A word boundary ("\b") is a spot between two characters that
     has a "\w" on one side of it and a "\W" on the other side of
     it (in either order), counting the imaginary characters off
     the beginning and end of the string as matching a "\W".

… so the \< probably comes from less(1)?

… hm, no. But, where then?

I used to use \b a lot, but \< and \> are just as easy to use, and POSIX. ;)

\w is nice, though. I think the closest POSIX one is [[:graph:]]? (Not super close, though)

@rl_dane @amin @kabel42 @sotolf @thedoctor \< and \> are not POSIX.

perlre(1) \w is identical to POSIX [a-zA-Z0-9_] in the C locale, so [[:alnum:]_] if you have support for POSIX character classes.

Ah, yes. [[:alnum:]] was the one I was thinking of.

@rl_dane @amin @kabel42 @sotolf @thedoctor but [[:alnum:]_]

Waiiiiit, what does the underscore before the second bracket do? I've never seen that before.

No mention of it in RE_FORMAT(7) on FreeBSD.

@rl_dane @amin @kabel42 @sotolf @thedoctor the exact same thing as the underscore in [a-zA-Z0-9_], and I’d be surprised if the FreeBSD manpage would not document it

@rl_dane @amin @kabel42 @sotolf @thedoctor let me blow your mind if that was news to you:

[[:alpha:][:digit:]_]

@mirabilos @rl_dane @amin @sotolf @thedoctor yay context sensitive [], there is no way that can go wrong \s

@mirabilos @rl_dane @amin @sotolf @thedoctor what would [:alpha:] do, and [:alpha]?

@kabel42 @rl_dane @amin @sotolf @thedoctor the same as [:ahlp]

@kabel42 @rl_dane @amin @sotolf @thedoctor see re_format(7)

RTFM re_format(7)

@mirabilos @rl_dane @amin @sotolf @thedoctor ok, so context sensitive, [ in [ is different from normal [