NAME
Acme::CPANModules::ReadingFilesBackward - Reading files backward (in
reverse)
VERSION
This document describes version 0.002 of
Acme::CPANModules::ReadingFilesBackward (from Perl distribution
Acme-CPANModules-ReadingFilesBackward), released on 2020-03-01.
DESCRIPTION
Reading files backward (in reverse).
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.
INCLUDED MODULES
* PerlIO::reverse
* File::ReadBackward
* File::Bidirectional
FAQ
What are ways to use this module?
Aside from reading it, you can install all the listed modules using
cpanmodules:
% cpanmodules ls-entries ReadingFilesBackward | cpanm -n
or Acme::CM::Get:
% perl -MAcme::CM::Get=ReadingFilesBackward -E'say $_->{module} for @{ $LIST->{entries} }' | cpanm -n
This module also helps lcpan produce a more meaningful result for "lcpan
related-mods" when it comes to finding related modules for the modules
listed in this Acme::CPANModules module.
HOMEPAGE
Please visit the project's homepage at
<https://metacpan.org/release/Acme-CPANModules-ReadingFilesBackward>.
SOURCE
Source repository is at
<https://github.com/perlancar/perl-Acme-CPANModules-ReadingFilesBackward
>.
BUGS
Please report any bugs or feature requests on the bugtracker website
<https://rt.cpan.org/Public/Dist/Display.html?Name=Acme-CPANModules-Read
ingFilesBackward>
When submitting a bug or request, please include a test-file or a patch
to an existing test-file that illustrates the bug or desired feature.
SEE ALSO
Acme::CPANModules::PickingRandomLinesFromFile
Acme::CPANModules - about the Acme::CPANModules namespace
cpanmodules - CLI tool to let you browse/view the lists
AUTHOR
perlancar <perlancar@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2020 by perlancar@cpan.org.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.