NAME Systemd::Util - Some utility routines related to Systemd VERSION This document describes version 0.002 of Systemd::Util (from Perl distribution Systemd-Util), released on 2019-06-17. FUNCTIONS systemd_is_running Usage: systemd_is_running() -> [status, msg, payload, meta] Check if systemd is running. Will return payload of 1 if systemd is running, 0 if not running, "undef" if cannot determine for sure. The result metadata "func.note" will give more details. The following heuristics are currently used: 1. Check if "/sbin/init" exists, if it does not the return 0. 2. Check if "/sbin/init" is a symlink to something with "systemd" in its name. If yes, then we return 1. We use Cwd's "realpath()" instead of "readlink()" here, to handle multiple redirection. 3. Check if "/lib/systemd/systemd" exists. Return 0 otherwise. 4. Check if "/sbin/init" is a hardlink to "/lib/systemd/systemd" by comparing its inode. Return 1 if it is. 5. Return undef otherwise, since we detect that "/lib/systemd/systemd" exists (systemd is installed) but we cannot be sure if it is running or not. When used as a CLI, this routine will exit 0 if systemd is running, 1 if systemd is not running, or 99 if cannot determine for sure. To see the more detailed note, you can run the CLI with "--json" to return the whole enveloped response. This function is not exported by default, but exportable. No arguments. Returns an enveloped result (an array). First element (status) is an integer containing HTTP status code (200 means OK, 4xx caller error, 5xx function error). Second element (msg) is a string containing error message, or 'OK' if status is 200. Third element (payload) is optional, the actual result. Fourth element (meta) is called result metadata and is optional, a hash that contains extra information. Return value: (any) HOMEPAGE Please visit the project's homepage at <https://metacpan.org/release/Systemd-Util>. SOURCE Source repository is at <https://github.com/perlancar/perl-Systemd-Util>. BUGS Please report any bugs or feature requests on the bugtracker website <https://rt.cpan.org/Public/Dist/Display.html?Name=Systemd-Util> 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 <email@example.com> COPYRIGHT AND LICENSE This software is copyright (c) 2019 by firstname.lastname@example.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.