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Postings from September 2021
* Scott Baker <scott@perturb.org> [2021-09-29 08:37:57 -0700]:
> On 9/29/21 08:21, Dan Book wrote:
> > On Wed, Sep 29, 2021 at 11:00 AM Tomasz Konojacki <me@xenu.pl> wrote:
> >
> > "-0777" flag is the usual way to read the whole file at once
> > (instead of
> > line by line) in one-liners.
> >
> > I feel this isn't ideal. "-0" is a bad flag. It's overly general,
> > users
> > rarely need $/ to be set to anything other than undef or "\n".
> > Also, the
> > input record separator has to be specified as an octal number,
> > which is
> > weird. The fact that the numbers above 0o377 are special-cased to mean
> > "undef" makes it even more confusing.
> >
> > Slurping is an extremely common operation and it deserves its own
> > one-letter flag. I propse "-g" (mnemonics: gobble, grab, gulp). I wish
> > it could be "-s", but sadly it's already taken :(
> >
> >
> > I think this is an excellent idea. This sort of processing using Perl
> > oneliners is extremely common and spread across the internet, and the
> > '-0777' flag is a constant source of confusion. Ideally perl would have
> > support for long options so we didn't have to take up the dwindling
> > one-letter options, but in the meantime, they are not in high demand so
> > IMO it's fine to use one for this.
Seems like anything would need to consider also -n and -l, any others? I'm not
a perl oneliner wizard by any means, but these two came up in my google.
#Note:
#$ perl -v
#This is perl 5, version 32, subversion 1 (v5.32.1) built for x86_64-netbsd-thread-multi
...
-0777, only
$ perl -0777 -MO=Deparse -e 'chomp; print $_' ./file.txt
BEGIN { $/ = undef; $\ = undef; }
chomp $_;
print $_;
-e syntax OK
-l, only
$ perl -l -MO=Deparse -e 'chomp; print $_' ./file.txt
BEGIN { $/ = "\n"; $\ = "\n"; }
chomp $_;
print $_;
-e syntax OK
-n, only
$ perl -n -MO=Deparse -e 'chomp; print $_' ./file.txt
LINE: while (defined($_ = readline ARGV)) {
chomp $_;
print $_;
}
-e syntax OK
-l -0777,
$ perl -l -0777 -MO=Deparse -e 'chomp; print $_' ./file.txt
BEGIN { $/ = undef; $\ = "\n"; }
chomp $_;
print $_;
-e syntax OK
-n -0777,
$ perl -n -0777 -MO=Deparse -e 'chomp; print $_' ./file.txt
BEGIN { $/ = undef; $\ = undef; }
LINE: while (defined($_ = readline ARGV)) {
chomp $_;
print $_;
}
-e syntax OK
-l -n -0777, (note "double chomp" - not quite sure where that came from)
$ perl -l -n -0777 -MO=Deparse -e 'chomp; print $_' ./file.txt
BEGIN { $/ = undef; $\ = "\n"; }
LINE: while (defined($_ = readline ARGV)) {
chomp $_;
chomp $_;
print $_;
}
-e syntax OK
Cheers,
Brett
ps: I like the idea of "long" options, too.
> >
> > -Dan
>
> I totally support this feature... and I think it should be a --long option
> instead of "-g". The Perl interpretter is *long overdue* for long options.
>
> - Scott
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