Systemd
=======
.. contents::

Service files
-------------

`service file man page <https://www.freedesktop.org/software/systemd/man/systemd.service.html#>`_

Next section says where to put the file.

After adding, run::

    # systemctl enable "unitname"
    # systemctl start "unitname"

Example/template::

   [Unit]
    Description={{ description }}
    Wants=network-online.target
    After=network-online.target

    [Service]
    Type=simple
    ExecStart={{ command }}
    Restart=on-failure  (or "always", "on-success", ...)
    # Run as:
    User={{ user }}
    Group={{ groupname }}
    # SupplementaryGroups=name1 name2 name3
    WorkingDirectory={{ directory }}

    [Install]
    WantedBy=multi-user.target


Unit search paths
-----------------

https://www.freedesktop.org/software/systemd/man/systemd.unit.html

System Unit Search Path::

        /etc/systemd/system.control/*
        /run/systemd/system.control/*
        /run/systemd/transient/*
        /run/systemd/generator.early/*
        /etc/systemd/system/*
        /etc/systemd/systemd.attached/*
        /run/systemd/system/*
        /run/systemd/systemd.attached/*
        /run/systemd/generator/*
        …
        /usr/lib/systemd/system/*
        /run/systemd/generator.late/*

User Unit Search Path::

        ~/.config/systemd/user.control/*
        $XDG_RUNTIME_DIR/systemd/user.control/*
        $XDG_RUNTIME_DIR/systemd/transient/*
        $XDG_RUNTIME_DIR/systemd/generator.early/*
        ~/.config/systemd/user/*
        /etc/systemd/user/*
        $XDG_RUNTIME_DIR/systemd/user/*
        /run/systemd/user/*
        $XDG_RUNTIME_DIR/systemd/generator/*
        ~/.local/share/systemd/user/*
        …
        /usr/lib/systemd/user/*
        $XDG_RUNTIME_DIR/systemd/generator.late/*

Journalctl
----------

* -e: skip to the end
* -x: more verbose about errors in the log
* -f: like tail -f, keep showing new entries
* -t, --identifier=syslog_identifier: show messages for syslog_identifier; Can be specified multiple times
* -g, --grep=pattern: what it sounds like