systemd-sleep.conf, sleep.conf.d - Suspend and hibernation configuration file
/etc/systemd/sleep.conf /etc/systemd/sleep.conf.d/*.conf /run/systemd/sleep.conf.d/*.conf /usr/lib/systemd/sleep.conf.d/*.conf
systemd supports three general power-saving modes: suspend a low-power state where execution of the OS is paused, and complete power loss might result in lost data, and which is fast to enter and exit. This corresponds to suspend, standby, or freeze states as understood by the kernel. hibernate a low-power state where execution of the OS is paused, and complete power loss does not result in lost data, and which might be slow to enter and exit. This corresponds to the hibernation as understood by the kernel. hybrid-sleep a low-power state where execution of the OS is paused, which might be slow to enter, and on complete power loss does not result in lost data but might be slower to exit in that case. This mode is called suspend-to-both by the kernel. Settings in these files determine what strings will be written to /sys/power/disk and /sys/power/state by systemd-sleep(8) when systemd(1) attempts to suspend or hibernate the machine.
The default configuration is defined during compilation, so a configuration file is only needed when it is necessary to deviate from those defaults. By default, the configuration file in /etc/systemd/ contains commented out entries showing the defaults as a guide to the administrator. This file can be edited to create local overrides. When packages need to customize the configuration, they can install configuration snippets in /usr/lib/systemd/*.conf.d/. Files in /etc/ are reserved for the local administrator, who may use this logic to override the configuration files installed by vendor packages. The main configuration file is read before any of the configuration directories, and has the lowest precedence; entries in a file in any configuration directory override entries in the single configuration file. Files in the *.conf.d/ configuration subdirectories are sorted by their filename in lexicographic order, regardless of which of the subdirectories they reside in. If multiple files specify the same option, the entry in the file with the lexicographically latest name takes precedence. It is recommended to prefix all filenames in those subdirectories with a two-digit number and a dash, to simplify the ordering of the files. To disable a configuration file supplied by the vendor, the recommended way is to place a symlink to /dev/null in the configuration directory in /etc/, with the same filename as the vendor configuration file.
The following options can be configured in the "[Sleep]" section of /etc/systemd/sleep.conf or a sleep.conf.d file: SuspendMode=, HibernateMode=, HybridSleepMode= The string to be written to /sys/power/disk by, respectively, systemd-suspend.service(8), systemd-hibernate.service(8), or systemd-hybrid-sleep.service(8). More than one value can be specified by separating multiple values with whitespace. They will be tried in turn, until one is written without error. If neither succeeds, the operation will be aborted. SuspendState=, HibernateState=, HybridSleepState= The string to be written to /sys/power/state by, respectively, systemd-suspend.service(8), systemd-hibernate.service(8), or systemd-hybrid-sleep.service(8). More than one value can be specified by separating multiple values with whitespace. They will be tried in turn, until one is written without error. If neither succeeds, the operation will be aborted.
Example: to exploit the “freeze” mode added in Linux 3.9, one can use systemctl suspend with [Sleep] SuspendState=freeze
systemd-sleep(8), systemd-suspend.service(8), systemd- hibernate.service(8), systemd-hybrid-sleep.service(8), systemd(1), systemd.directives(7)
Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.
Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.
Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.
Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.
The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.
Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.
Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.
Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.