RTCWAKE(8)

💤 RTCWAKE(8) 💤

okay bestie, so this is the rtcwake manual page from the system administration corner of the internet — yes it's section 8, we're in the big leagues now 💅. Here's the whole thing, no skips, no skimming.

✨ NAME ✨

rtcwake — enter a system sleep state until specified wakeup time

🦋 SYNOPSIS 🦋

rtcwake [options] [-d device] [-m standby_mode] {-s seconds|-t time_t}

🌸 DESCRIPTION 🌸

So like, this program is the one that puts your system to sleep AND sets an alarm so it wakes itself back up at a time you pick. It's giving "nap with a purpose" fr fr.

It uses cross-platform Linux interfaces to slip into a system sleep state, and it will leave that state no later than the time you specified. It plays nice with any RTC framework driver that supports standard driver model wakeup flags. 👑

Normally you'd use it the way people used the old apmsleep utility — to wake up from a suspend state like ACPI S1 (standby) or S3 (suspend-to-RAM). And the slay part? Most platforms can do those without needing analogues of BIOS, APM, or ACPI. no cap.

On some systems it can also do the nvram-wakeup thing, waking from states like ACPI S4 (suspend to disk). > Heads up though: not all systems have persistent media that are appropriate for those suspend modes, so vibe check your hardware first.

Also, alarm functionality depends on hardware — not every RTC is able to set up an alarm up to 24 hours in the future. 😭 It's not a universal power, bestie.

And one more thing: the suspend setup may get interrupted by active hardware. Example? Wireless USB input devices that keep sending events for some fraction of a second after the return key is pressed. rtcwake tries to avoid this problem and it waits for the terminal to settle down before entering a system sleep. so polite of it honestly 🫶

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💖 OPTIONS 💖

• -A, --adjfile file — Specify an alternative path to the adjust file.
• -a, --auto — Read the clock mode (whether the hardware clock is set to UTC or local time) from the adjtime file, where hwclock(8) stores that information. This is the default. ✨
• --date timestamp — Set the wakeup time to the value of this timestamp. The format of timestamp can be any of the following:

YYYYMMDDhhmmss
"YYYY-MM-DD hh:mm:ss"
"YYYY-MM-DD hh:mm"      (seconds is 00)
YYYY-MM-DD              (time is 00:00:00)
hh:mm:ss                (date is today)
hh:mm                   (date is today, seconds is 00)
+number[smhd]           (seconds/minutes/hours/days after now)
tomorrow                (time is 00:00:00)

Examples of the +number[smhd] format are: +5m, +6h, +2d. And the unit specifier may be longer: +5min, +6hours, +2days. so flexible, we love her 🌈

• -d, --device device — Use the specified device instead of rtc0 as realtime clock. This option is only relevant if your system has more than one RTC. You may specify rtc1, rtc2, ... here.
• -l, --local — Assume that the hardware clock is set to local time, regardless of the contents of the adjtime file.
• --list-modes — List available --mode option arguments.
• -m, --mode mode — Go into the given standby state. Valid values for mode are:
  • standby — ACPI state S1. This state offers minimal, though real, power savings, while providing a very low-latency transition back to a working system. This is the default mode. 💤
  • freeze — The processes are frozen, all the devices are suspended and all the processors idled. This state is a general state that does not need any platform-specific support, but it saves less power than Suspend-to-RAM, because the system is still in a running state. (Available since Linux 3.9.)
  • mem — ACPI state S3 (Suspend-to-RAM). This state offers significant power savings as everything in the system is put into a low-power state, except for memory, which is placed in self-refresh mode to retain its contents.
  • disk — ACPI state S4 (Suspend-to-disk). This state offers the greatest power savings, and can be used even in the absence of low-level platform support for power management. This state operates similarly to Suspend-to-RAM, but includes a final step of writing memory contents to disk.
  • off — ACPI state S5 (Poweroff). This is done by calling /sbin/shutdown. Not officially supported by ACPI, but it usually works. 💀
  • no — Don't suspend, only set the RTC wakeup time.
  • on — Don't suspend, but read the RTC device until an alarm time appears. This mode is useful for debugging. 🔍
  • disable — Disable a previously set alarm.
  • show — Print alarm information in format: "alarm: off|on <time>". The time is in ctime(3) output format, e.g., "alarm: on Tue Nov 16 04:48:45 2010".
• -n, --dry-run — This option does everything apart from actually setting up the alarm, suspending the system, or waiting for the alarm. practice run, main character rehearsal energy 🎀
• -s, --seconds seconds — Set the wakeup time to seconds in the future from now.
• -t, --time time_t — Set the wakeup time to the absolute time time_t. time_t is the time in seconds since 1970-01-01, 00:00 UTC. Use the date(1) tool to convert between human-readable time and time_t.
• -u, --utc — Assume that the hardware clock is set to UTC (Universal Time Coordinated), regardless of the contents of the adjtime file.
• -v, --verbose — Be verbose. spill the tea, tell us everything 🗣️
• -h, --help — Display help text and exit.
• -V, --version — Display version and exit.

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📝 NOTES 📝

Some PC systems can't currently exit sleep states such as mem using only the kernel code accessed by this driver. They need help from userspace code to make the framebuffer work again. teamwork makes the dream work, ig 😭

📁 FILES 📁

• /etc/adjtime

📜 HISTORY 📜

The program was posted several times on LKML and other lists before appearing in kernel commit message for Linux 2.6 in the GIT commit 87ac84f42a7a580d0dd72ae31d6a5eb4bfe04c6d. she's been around, she's iconic, she's got lore 🌟

👑 AUTHORS 👑

The program was written by David Brownell <dbrownell@users.sourceforge.net> and improved by Bernhard Walle <bwalle@suse.de>.

⚖️ COPYRIGHT ⚖️

This is free software. You may redistribute copies of it under the terms of the GNU General Public License <http://www.gnu.org/licenses/gpl.html>. There is NO WARRANTY, to the extent permitted by law. (yes the NO WARRANTY is in all caps in the original, that's not me being dramatic, that's just the law 💅)

🫶 SEE ALSO 🫶

adjtime_config(5), hwclock(8), date(1)

🐛 REPORTING BUGS 🐛

For bug reports, use the issue tracker <https://github.com/util-linux/util-linux/issues>.

📦 AVAILABILITY 📦

The rtcwake command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.

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okay that's the whole page bestie, you ate it, no crumbs left 🌈💖 and for the cute sign-off: this lil masterpiece is from util-linux 2.42.4, dated 2026-09-21, and it lives as RTCWAKE(8) — go set an alarm and take that nap, you deserve it 🦋✨