Acme-CPANModules-ReadingFilesBackward
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NAME
Acme::CPANModules::ReadingFilesBackward - List of modules to read files
backward (in reverse)
VERSION
This document describes version 0.003 of
Acme::CPANModules::ReadingFilesBackward (from Perl distribution
Acme-CPANModules-ReadingFilesBackward), released on 2023-10-31.
DESCRIPTION
Probably the fastest way, if you are on a Unix system, is to use the tac
command, which can read a file line by line in reverse order, or
paragraph by paragraph, or character by character, or word by word, or
by a custom separator string or regular expression. Example for using it
from Perl:
open my $fh, "tac /etc/passwd |";
print while <$fh>;
Another convenient way is to use the Perl I/O layer PerlIO::reverse. It
only does line-by-line reversing, but you can use the regular Perl API.
You don't even have to "use" the module explicitly (but of course you
have to get it installed first):
open my $fh, "<:reverse", "/etc/passwd";
print while <$fh>;
If your file is small (fits in your system's memory), you can also slurp
the file contents first into an array (either line by line, or paragraph
by paragraph, or what have you) and then simply "reverse" the array:
open my $fh, "<", "/etc/passwd";
my @lines = <$fh>;
print for reverse @lines;
If the above solutions do not fit your needs, there are also these
modules which can help: File::ReadBackward, File::Bidirectional.
File::ReadBackward is slightly faster than File::Bidirectional, but
File::Bidirectional can read forward as well as backward. I now simply
prefer PerlIO::reverse because I don't have to use a custom API for
reading files.
ACME::CPANMODULES ENTRIES
PerlIO::reverse
Author: GFUJI <https://metacpan.org/author/GFUJI>
File::ReadBackward
File::Bidirectional
Author: KIANWIN <https://metacpan.org/author/KIANWIN>
FAQ
What is an Acme::CPANModules::* module?
An Acme::CPANModules::* module, like this module, contains just a list
of module names that share a common characteristics. It is a way to
categorize modules and document CPAN. See Acme::CPANModules for more
details.
What are ways to use this Acme::CPANModules module?
Aside from reading this Acme::CPANModules module's POD documentation,
you can install all the listed modules (entries) using cpanm-cpanmodules
script (from App::cpanm::cpanmodules distribution):
% cpanm-cpanmodules -n ReadingFilesBackward
Alternatively you can use the cpanmodules CLI (from App::cpanmodules
distribution):
% cpanmodules ls-entries ReadingFilesBackward | cpanm -n
or Acme::CM::Get:
( run in 0.868 second using v1.01-cache-2.11-cpan-df04353d9ac )