ADJTIME_CONFIG(5)

💖 ADJTIME_CONFIG — the whole vibe 💖

okay so bestie, this is adjtime_config, aka the file format page from the adjtime_config(5) manual. it's all about your hardware clock's settings and drift factor. literally the little file that keeps your RTC in check. 🕰️✨

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🌸 NAME 🌸

adjtime_config — all the tea about your hardware clock setting and its drift factor 💅

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🎀 SYNOPSIS 🎀

/etc/adjtime

that's it. that's the whole thing. iconic. 👑

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✨ DESCRIPTION ✨

so the file /etc/adjtime holds descriptive info about the hardware mode clock setting and the clock drift factor. it gets read and written by hwclock(8), and it gets read by programs like rtcwake to figure out the RTC time mode. 🫶

normally it lives in /etc, but tools like hwclock(8) or rtcwake(8) can use a different location via command line options if you don't want write access to /etc. and if the file is just... missing? the default clock mode is "UTC". no biggie. 💫

here's the thing though — the Hardware Clock is usually not very accurate, bestie. 😭 but the good news is that most of its inaccuracy is completely predictable — it gains or loses the same amount of time every single day. that's what we call systematic drift. the util hwclock(8) keeps the file /etc/adjtime to hold onto some of that historical info. for more details, go read the "The Adjust Function" and "The Adjtime File" sections in the hwclock(8) man page. iykyk. 📖

also the adjtime file is formatted in plain ASCII. old school, but it works. 🧚

🌈 First line

three numbers, separated by blanks:

• drift factor — the systematic drift rate in seconds per day (floating point decimal)
• last adjust time — the resulting number of seconds since 1969 UTC of the most recent adjustment or calibration (decimal integer)
• adjustment status — zero (for compatibility with clock(8)) as a floating point decimal

🦋 Second line

• last calibration time — the resulting number of seconds since 1969 UTC of the most recent calibration. it's zero if there has been no calibration yet, or if it's known that any previous calibration is moot (for example, because the Hardware Clock has been found, since that calibration, not to contain a valid time). this one is a decimal integer. ⭐

🍓 Third line

• clock mode — supported values are UTC or LOCAL. it tells you whether the Hardware Clock is set to Coordinated Universal Time or local time. and you can always override this value with options on the hwclock(8) command line. you have the power, bestie. 💪👑

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📁 FILES 📁

• /etc/adjtime

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👀 SEE ALSO 👀

hwclock(8), rtcwake(8)

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🙈 REPORTING BUGS 🙈

found a bug? for bug reports, use the issue tracker at <https://github.com/util-linux/util-linux/issues>. don't be shy, they wanna know. 🐛💖

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🌟 AVAILABILITY 🌟

adjtime_config is part of the util-linux package, which you can download from the Linux Kernel Archive at <https://www.kernel.org/pub/linux/utils/util-linux/>. go get it. 🫶

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and that's the whole page, bestie!! this was util-linux 2.42.4, dated 2026-09-21, for ADJTIME_CONFIG(5). mwah, slay, go forth and know your hardware clock 💅🎀✨