after - Run command after delay and/or other conditions
This document describes version 0.02 of after (from Perl distribution App-after), released on 2016-04-18.
Usage:
% after [options] <command>...
Examples:
Run command after 30-minute delay:
% after --delay 30m cmd
Run command after 12 hour delay and time has passed 2016-04-18:
% after --delay 12h --time 2016-04-18 cmd
Run command after 12 hour delay *or* time has passed 2016-04-18:
% after --or --delay 12h --time 2016-04-18 cmd
Run command after system uptime is 2 days:
% after --uptime 2d cmd
Run command after system load is above 2.5:
% after --load-above 2.5 cmd
Run command after system load is between 1 and 5:
% after --load-above 1 --load-below 5 cmd
after will run command after all the specified conditions are met. A condition can be: delay (--delay), current time (--time), system uptime (--uptime), system load falling below a certain value (--load-below), system load rising above a certain value (--load-above). More conditions will be available in the future.
after
--delay
--time
--uptime
--load-below
--load-above
* marks required options.
*
Set path to configuration file.
Can be specified multiple times.
Set configuration profile to use.
Do not use any configuration file.
Do not read environment for default options.
Run command after all conditions are met (the default).
Run command when none (instead of all) of the conditions are met.
Run command after one condition (instead of all) is met.
Choose output format, e.g. json, text.
Default value:
undef
Set output format to json.
When outputing as JSON, strip result envelope.
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]
See --command.
--command
Display help message and exit.
Display program's version and exit.
This script has shell tab completion capability with support for several shells.
To activate bash completion for this script, put:
complete -C after after
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.
~/.bashrc
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.
shcompgen
To activate tcsh completion for this script, put:
complete after 'p/*/`after`/'
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.
~/.tcshrc
It is also recommended to install shcompgen (see above).
For fish and zsh, install shcompgen as described above.
This script can read configuration file, which by default is searched at ~/.config/after.conf, ~/after.conf or /etc/after.conf (can be changed by specifying --config-path). All found files will be read and merged.
--config-path
To disable searching for configuration files, pass --no-config.
--no-config
Configuration file is in the format of IOD, which is basically INI with some extra features.
You can put multiple profiles in a single file by using section names like [profile=SOMENAME] (filter by profile). Those sections will only be read if you specify the matching --config-profile SOMENAME.
[profile=SOMENAME]
--config-profile SOMENAME
You can also put configuration for multiple programs inside a single file, and use filter program=NAME in section names, e.g. [program=foo ...]. The section will then only be used when the reading program matches.
program=NAME
[program=foo ...]
Finally, you can filter a section by environment variable using the filter env=CONDITION in section names. For example if you only want a section to be read if a certain environment variable is true: [env=SOMEVAR ...]. If you only want a section to be read when the value of an environment variable has value equals something: [env=HOSTNAME=blink ...]. If you only want a section to be read when the value of an environment variable does not equal something: [env=HOSTNAME!=blink ...]. If you only want a section to be read when an environment variable contains something: [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.
env=CONDITION
[env=SOMEVAR ...]
[env=HOSTNAME=blink ...]
[env=HOSTNAME!=blink ...]
[env=HOSTNAME*=server ...]
List of available configuration parameters:
all (see --all) command (see --command) delay (see --delay) format (see --format) load_above (see --load-above) load_below (see --load-below) naked_res (see --naked-res) none (see --none) or (see --or) time (see --time) uptime (see --uptime)
Specify additional command-line options
~/.config/after.conf
~/after.conf
/etc/after.conf
Please visit the project's homepage at https://metacpan.org/release/App-after.
Source repository is at https://github.com/perlancar/perl-App-after.
Please report any bugs or feature requests on the bugtracker website https://rt.cpan.org/Public/Dist/Display.html?Name=App-after
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.
http://onegeek.org/~tom/software/delay/. This CLI can also be used to run a command after specified delay or point of time.
Proc::Govern. This module can be used to run a command then pause it when system load is outside specified range. The distribution also comes with a CLI script.
perlancar <perlancar@cpan.org>
This software is copyright (c) 2016 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.
To install App::after, copy and paste the appropriate command in to your terminal.
cpanm
cpanm App::after
CPAN shell
perl -MCPAN -e shell install App::after
For more information on module installation, please visit the detailed CPAN module installation guide.