NAME

pick-random-lines - Pick one or more random lines from input

VERSION

This document describes version 0.01 of main (from Perl distribution App-PickRandomLines), released on 2015-11-23.

SYNOPSIS

Usage:

 % pick-random-lines [options] [files]...

DESCRIPTION

TODO: * option to allow or disallow duplicates

OPTIONS

* marks required options.

Output options

--format=s

Choose output format, e.g. json, text.

Default value:

 undef
--json

Set output format to json.

--naked-res

When outputing as JSON, strip result envelope.

Default value:

 0

By default, when outputing as JSON, the full enveloped result is returned, e.g.:

    [200,"OK",[1,2,3],{"func.extra"=>4}]

The reason is so you can get the status (1st element), status message (2nd element) as well as result metadata/extra result (4th element) instead of just the result (3rd element). However, sometimes you want just the result, e.g. when you want to pipe the result for more post-processing. In this case you can use `--naked-res` so you just get:

    [1,2,3]

Other options

--algorithm=s

Default value:

 "scan"

Valid values:

 ["scan","seek"]

`scan` is the algorithm described in the `perlfaq` manual (`perldoc -q "random line"). This algorithm scans the whole input once and pick one or more lines randomly from it.

`seek` is the algorithm employed by the Perl module `File::RandomLine`. It works by seeking a file randomly and finding the next line (repeated `n` number of times). This algorithm is faster when the input is very large as it avoids having to scan the whole input. But it requires that the input is seekable (a single file, stdin is not supported and currently multiple files are not supported as well). *Might produce duplicate lines*.

--file=filename

If none is specified, will get input from stdin.

Can be specified multiple times.

--files-json=filename

See --file.

--help, -h, -?

Display help message and exit.

--num-lines=i, -n

Default value:

 1

If input contains less lines than the requested number of lines, then will only return as many lines as the input contains.

--version, -v

Display program's version and exit.

COMPLETION

The distribution comes with a shell completer script (_pick-random-lines) for this script.

bash

To activate bash completion for this script, put:

 complete -C _pick-random-lines pick-random-lines

in your bash startup (e.g. ~/.bashrc). Your next shell session will then recognize tab completion for the command. Or, you can also directly execute the line above in your shell to activate immediately.

It is recommended, however, that you install shcompgen which allows you to activate completion scripts for several kinds of scripts on multiple shells. Some CPAN distributions (those that are built with Dist::Zilla::Plugin::GenShellCompletion) will even automatically enable shell completion for their included scripts (using shcompgen) at installation time, so you can immadiately have tab completion.

tcsh

To activate tcsh completion for this script, put:

 complete _pick-random-lines 'p/*/`pick-random-lines`/'

in your tcsh startup (e.g. ~/.tcshrc). Your next shell session will then recognize tab completion for the command. Or, you can also directly execute the line above in your shell to activate immediately.

It is also recommended to install shcompgen (see above).

other shells

For fish and zsh, install shcompgen as described above.

HOMEPAGE

Please visit the project's homepage at https://metacpan.org/release/App-PickRandomLines.

SOURCE

Source repository is at https://github.com/perlancar/perl-App-PickRandomLines.

BUGS

Please report any bugs or feature requests on the bugtracker website https://rt.cpan.org/Public/Dist/Display.html?Name=App-PickRandomLines

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.

AUTHOR

perlancar <perlancar@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2015 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.