Re: 'safe' printing to the terminal

[email protected] ("H.Merijn Brand" via perl5-porters) Mon, 11 May 2026 11:50:49 +0200

Newsgroups	perl.perl5.porters
Message-ID	<20260511115013.7df505d2@pc09>

On Sun, 10 May 2026 17:47:38 +0200, Aristotle Pagaltzis via perl5-porters <[email protected]> wrote:

> * Michiel Beijen <[email protected]> [2026-05-09 14:51]:
> > Is there a 'best practice' way to achieve something similar in Perl?  
> 
> I don’t think so. I don’t know the entire CPAN off the top of my head,
> obviously, but I’ve been around CPAN for a while and I don’t remember
> ever coming across anything like that.
> 
> A probably-easily-90% fix is to just escape the escape character (0x1B),
> but I have no guess for how much complexity is necessary to get to 100%.

Note that quite a lot of ANSI-compliant devices *also* support the
8-bit Fe/C1 versions of escape sequences (e.g. \e[ can be abbreviated
to \x9b)

See https://en.wikipedia.org/wiki/ANSI_escape_code#Fe_Escape_sequences

> > I know there used to be a discussion about this in gnu coreutils (ls
> > and friends) and there is now quotearg.c which is MANY lines of code.  
> 
> The place I’d be most inclined to look would be the source of the `less`
> pager… but it’s not a pleasant codebase for finding or isolating that
> logic. :-/  (It has a toggle for whether to pass escape sequences
> through or escape them, which is stored in the `ctldisp` variable. You
> can start with that symbol and lose your mind from there…)
> 
> 
> * David Christensen <[email protected]> [2026-05-09 23:55]:
> > https://metacpan.org/pod/String::ShellQuote
> >
> > I would advise testing what shell_quote() does when given control
> > characters, ANSI escape sequences, Unicode, etc..  
> 
> That is not really applicable. Maybe it happens to work for that purpose
> by accident, but terminal control sequence escaping is a completely
> different animal from shell metacharacter quoting.


-- 
H.Merijn Brand  https://tux.nl   Perl Monger   http://amsterdam.pm.org/
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