Show threadR.L. Dane    🍵 Feb 8

@mirabilos @kabel42 @amin @sotolf @thedoctor

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.

Show threadmirabilosFeb 8

@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.

Show threadR.L. Dane    🍵 Feb 8

@mirabilos @amin @kabel42 @sotolf @thedoctor

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

Show threadmirabilosFeb 8

@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.

Show threadmirabilosFeb 8

@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?

Show threadR.L. Dane    🍵 Feb 8

@mirabilos @amin @kabel42 @sotolf @thedoctor

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)

Show threadmirabilosFeb 8

@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.

Show threadR.L. Dane    🍵 Feb 8

@mirabilos @amin @kabel42 @sotolf @thedoctor

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

Show threadmirabilosFeb 8
@rl_dane @amin @kabel42 @sotolf @thedoctor but [[:alnum:]_]
Show threadR.L. Dane    🍵 Feb 8

@mirabilos @amin @kabel42 @sotolf @thedoctor

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.

Show threadmirabilosFeb 8
@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
Show threadmirabilosFeb 8

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

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

Show threadkabel42Feb 8
@mirabilos @rl_dane @amin @sotolf @thedoctor yay context sensitive [], there is no way that can go wrong \s
Show threadmirabilosFeb 8
@kabel42 @rl_dane @amin @sotolf @thedoctor it’s actually not, the first unescaped [ switches from RE context to RE-Bracket context in the bracket-begin state, in which you can have an optional ^ (except in shellglobs where it is spelt !), then an optional ] not taken as the end of the RE-Bracket, then an optional -, then any amount of expressions of the type a-z, [:charclass:], [=equivalenceclass=], x, then an optional -, then a closing ] which terminates the RE-Bracket context.
Show threadmirabilosFeb 8
@kabel42 @rl_dane @amin @sotolf @thedoctor (I erred: you can have either the ] or the - at the beginning, not both)
Show threadmirabilosFeb 8
@kabel42 @rl_dane @amin @sotolf @thedoctor (and I forgot collating elements, which is totally fucked up, [a[.ch.]] in e.g. es_ES.UTF-8 matches either a or ch, so a bracket expression in POSIX has a variable matching length…)
Show threadkabel42Feb 8
@mirabilos @rl_dane @amin @sotolf @thedoctor yeah, i hate it
Show threadmirabilosFeb 8
@kabel42 @rl_dane @amin @sotolf @thedoctor these are rare-to-never-used features, thankfully
Show threadmirabilosFeb 8
@kabel42 @rl_dane @amin @sotolf @thedoctor tbh the only time I use something other than simple chars and ranges in bracket expressions is the BSD [[:<:]] and [[:>:]] extension (which matches a zero-length string)
Show threadkabel42Feb 8
@mirabilos @rl_dane @amin @sotolf @thedoctor as in '^$'?
Show threadmirabilosFeb 8
@kabel42 @rl_dane @amin @sotolf @thedoctor no, the zero-length string between a nōn-word‑ and a word character
Show threadkabel42Feb 8
@mirabilos @rl_dane @amin @sotolf @thedoctor nōn-word?
Show threadR.L. Dane    🍵 Feb 8

@kabel42 @mirabilos @amin @sotolf @thedoctor

Basically spaces and punctuation.

Show threadmirabilosFeb 8
@rl_dane @kabel42 @amin @sotolf @thedoctor no, literally [^a-zA-Z0-9_]
Show threadkabel42Feb 8
@mirabilos @rl_dane @amin @sotolf @thedoctor and ^ here is negation?
Show threadmirabilosFeb 8
@kabel42 @rl_dane @amin @sotolf @thedoctor no, [^char-class] matches “any single character, other than newline, not in char-class”
Show threadkabel42Feb 8
@mirabilos @rl_dane @amin @sotolf @thedoctor yeah, basically what i meant except for the newline maybe
Show threadmirabilosFeb 8

@kabel42 @rl_dane @amin @sotolf @thedoctor yea, I’m just pedantic.

In the RE ^foo[^bar^]baz$ there technically are exactly two carets.

Show threadmirabilosFeb 8
@kabel42 @rl_dane @amin @sotolf @thedoctor this is important when you want to include a ] or - in a bracket expression, and for the newline ofc.
Show threadR.L. Dane    🍵 Feb 9

@mirabilos @kabel42 @amin @sotolf @thedoctor

Don't you have to backslash escape a right bracket, like [a-z\]]?

Show threadmirabilosFeb 9
@sotolf @thedoctor @amin @rl_dane @kabel42 not if it’s the first character of a bracket expression, like []a-z]
Show threadR.L. Dane    🍵 Feb 9

@mirabilos @sotolf @thedoctor @amin @kabel42

Ahhhh, good to know. Mentally filed. ;)

Show threadmirabilosFeb 9

@kabel42 @amin @thedoctor @sotolf @rl_dane I often go through logs by first cutting off timestamp
and host using rectangle mode in jupp, then replacing ^([^ ]*)\[[^]]*\]: with \1: and sort -uing.

I’ve also used [][0-9a-fA-F:] to match IP addresses…

Show threadR.L. Dane    🍵 Feb 9

@mirabilos @kabel42 @amin @thedoctor @sotolf

I love editors with rectangle selection and editing modes. vim has it, and my first exposure to it was actually in Microsoft Word 4.0 for mac. Obviously not something I use today. XD

Show threadkabel42Feb 9
@rl_dane @mirabilos @amin @thedoctor @sotolf kate had that for a time and now i can't find it anymore... :(
Show threadmirabilosFeb 9
@rl_dane @kabel42 @sotolf @thedoctor @amin jupp :p
Show threadR.L. Dane    🍵 Feb 9

@mirabilos @kabel42 @sotolf @thedoctor @amin

Respect to your efforts, but for me, it's modal editing or die. XD

Show threadmirabilosFeb 9
@rl_dane @kabel42 @sotolf @thedoctor @amin just imagine ^K and ^Q as starting the action and movement modes, respectively, and otherwise you’re in insert mode, with a few shortcuts
Show threadR.L. Dane    🍵 Feb 9

@mirabilos @kabel42 @sotolf @thedoctor @amin

Maybe if I had caps lock mapped to control, rather than escape. ;)

Show threadmirabilosFeb 9
@thedoctor @kabel42 @amin @rl_dane @sotolf solvable problem ;) PCs (including my first) did have Control there, after all
Show threadR.L. Dane    🍵 

@mirabilos @thedoctor @kabel42 @amin @sotolf

I don't recall seeing anything other than unix terminals and workstations with control to the left of "A"

But yeah, capslock is a dumb key, or at least, that's a dumb placement for it. ;)

Feb 9 at 2:12amWeb
Show threadmirabilosFeb 9
@rl_dane @thedoctor @kabel42 @amin @sotolf https://commons.wikimedia.org/wiki/File:IBM_Model_F_XT.png used to be the standard layout for PCs, though the F keys could also go up to where they are now (only up to and including F10, mind you)
File:IBM Model F XT.png - Wikimedia Commons

Show threadmirabilosFeb 9
@rl_dane @thedoctor @kabel42 @amin @sotolf and here I thought you were older than me?
Show threadR.L. Dane    🍵 Feb 9

@mirabilos @thedoctor @kabel42 @amin @sotolf

Maybe? I'm half a century, roughly. ;)

Show threadR.L. Dane    🍵 Feb 9

@mirabilos @thedoctor @kabel42 @amin @sotolf

Ah, yes, that was the very first IBM PC keyboard, the one that didn't have dedicated arrow keys. I never spent much time in front of one (possibly none, not sure), but I was aware of it.

I just didn't realize it had Ctrl in the "correct" position. ^___^

Show threadmirabilosFeb 9
@rl_dane @thedoctor @kabel42 @amin @sotolf I spent a lot of time in front of this one…
Show threadR.L. Dane    🍵 Feb 9

@mirabilos @thedoctor @kabel42 @amin @sotolf

Whoa, there's some seriously unused space on the surface of that keyboard. XD

Someone should have showed them the Amiga 500 ;)

Show threadmirabilosFeb 9

@rl_dane @thedoctor @kabel42 @amin @sotolf huh,

Not much, just the palm rest and where the winkeys are these days.

Show threadsotolfFeb 9
@mirabilos @rl_dane @thedoctor @kabel42 @amin I think he means to the right where the diskette station ist, but it makes sense, because I think the Schneider PC has all the guts in the keyboard.
Show threadmirabilosFeb 9

@rl_dane @thedoctor @kabel42 @amin @sotolf ah but the whole thing is just as high as needed to fit the floppy disc drive.

All the guts are under the keyboard, INCLUDING an ISA slot for extension cards (out of the back at the very left), and all the connectors (HGC/CGA TTL monitor, serial, parallel, power, external HDD connector, external second FDD connector) are also on the back, as is the power button.