20 Aug 2020 00:05:53 UTC
- Distribution: App-PickRandomLines
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- Perl: v5.10.1
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pick-random-lines - Pick one or more random lines from input
This document describes version 0.020 of main (from Perl distribution App-PickRandomLines), released on 2020-04-29.
% pick-random-lines [--algorithm=s] [--config-path=path+] [--config-profile=profile] [--format=name] [--json] [-n=s] [--(no)naked-res] [--no-config] [--no-env] [--num-lines=s] [--page-result[=program]] [files] ...
TODO: * option to allow or disallow duplicates
*marks required options.
`scan` is the algorithm described in the `perlfaq` manual (`perldoc -q "random line"). This algorithm scans the whole input once and picks 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*.
If none is specified, will get input from stdin.
Can be specified multiple times.
- --num-lines=s, -n
If input contains less lines than the requested number of lines, then will only return as many lines as the input contains.
Set path to configuration file.
Can be specified multiple times.
Set configuration profile to use.
Do not use any configuration file.
Choose output format, e.g. json, text.
Set output format to json.
When outputing as JSON, strip result envelope.
By default, when outputing as JSON, the full enveloped result is returned, e.g.:
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:
Filter output through a pager.
The script comes with a companion shell completer script (_pick-random-lines) for this script.
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 modules using cpanm-shcompgen which can activate shell completion for scripts immediately.
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).
For fish and zsh, install shcompgen as described above.
This script can read configuration files. Configuration files are in the format of IOD, which is basically INI with some extra features.
By default, these names are searched for configuration filenames (can be changed using
--config-path): ~/.config/pick-random-lines.conf, ~/pick-random-lines.conf, or /etc/pick-random-lines.conf.
All found files will be read and merged.
To disable searching for configuration files, pass
You can put multiple profiles in a single file by using section names like
[SOMESECTION profile=SOMENAME]. Those sections will only be read if you specify the matching
You can also put configuration for multiple programs inside a single file, and use filter
program=NAMEin section names, e.g.
[SOMESECTION program=NAME]. The section will then only be used when the reading program matches.
Finally, you can filter a section by environment variable using the filter
env=CONDITIONin section names. For example if you only want a section to be read if a certain environment variable is true:
[SOMESECTION env=SOMEVAR ...]. If you only want a section to be read when the value of an environment variable has value equals something:
[SOMESECTION env=HOSTNAME=blink ...]. If you only want a section to be read when the value of an environment variable does not equal something:
[SOMESECTION env=HOSTNAME!=blink ...]. If you only want a section to be read when an environment variable contains something:
[SOMESECTION env=HOSTNAME*=server ...]. Note that currently due to simplistic parsing, there must not be any whitespace in the value being compared because it marks the beginning of a new section filter or section name.
List of available configuration parameters:
algorithm (see --algorithm) files (see --file) format (see --format) naked_res (see --naked-res) num_lines (see --num-lines)
Specify additional command-line options.
Please visit the project's homepage at https://metacpan.org/release/App-PickRandomLines.
Source repository is at https://github.com/perlancar/perl-App-PickRandomLines.
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.
This software is copyright (c) 2020 by email@example.com.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.
Module Install Instructions
To install App::PickRandomLines, copy and paste the appropriate command in to your terminal.
perl -MCPAN -e shell install App::PickRandomLines
For more information on module installation, please visit the detailed CPAN module installation guide.