Re: trivial question

[Ray Andrews <rayandrews@eastlink.ca>]

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On 2022-12-05 20:29, Bart Schaefer wrote:
>
> If you're asking what else are glob characters, you should probably
> attempt to understand the corresponding manual section.
>
If a word contains an unquoted instance of one of the characters ‘*’, 
‘(’, ‘|’, ‘<’, ‘[’, or ‘?’, it is regarded as a pattern for filename 
generation, unless the GLOB option is unset. If the EXTENDED_GLOB option 
is set, the ‘^’ and ‘#’ characters also denote a pattern; otherwise they 
are not treated specially by the shell.

What overloads me is the way pattern globbing (do we say that? or just 
call it 'pattern matching'?) and filename globbing are conflated in 
there.  So very similar but so subtly different. Anyway stuff is 
starting to stick to the inside of my skull.   At the very least I know 
where to expect trouble.  Obviously it's decades late to complain about 
any of this, but life would be simpler if it was explicit that one 
wanted to generate filenames or one wanted strings to be strings.  That 
way there'd be no need for a list of special characters. I know that 
echo doesn't decide how it's arguments will be handled, still it's 
intuitive that one echos a string.  But I suppose the rule is to quote 
anything you want to be immune to such expansions and it's as simple as 
that. Unquote and you're taking your chances.  Fair enough.  It's an 
early lesson.

Lawrence:

> You can observe this with XTRACE:

Gotta spend more time with that.  Output can be a bit overwhelming but slow and steady -- the information is in there.
A better tool is "typeset -p", which outputs an accurate (albeit
sometimes difficult-to-read) representation.

	% typeset -p arr
	typeset -a arr=( $'a\nb\C-Mc' $'d\C-Me\nf' )

Yes! It almost doesn't matter that it's hard to read, the point is to catch that one is not the same as the other.  Yup, that's a life-lesson.

Peter:

There's the special case of the GLOB_ASSIGN option where all
assignments, not just arrays, undergo globbing.  That's for
compatibility with early versions of zsh, otherwise it's very
confusing.

Deus absit.  What I might like is some way of turning it all off.  Like unsetopt glob, yes?  Actually, tho it started out as a purely academic question, I can now think of a place where I think I'll want to do that.



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