UPSLOG(8)

NUT Manual

UPSLOG(8)

NAME¶

upslog - UPS status logger

SYNOPSIS¶

upslog -h

upslog [OPTIONS]

DESCRIPTION¶

upslog is a daemon that will poll a UPS at periodic intervals, fetch the variables that interest you, format them, and write them to a file.

The default format string includes variables that are supported by many common UPS models. See the description below to make your own.

OPTIONS¶

-f format

Monitor the UPS using this format string. Be sure to enclose format in quotes so your shell doesn’t split it up. Valid escapes within this string are:

Insert a single "%"

Insert a single TAB character (like printf("\t"))

%TIME format%

Insert the time with strftime formatting

%ETIME%

Insert the number of seconds since the start of "Epoch", ala time_t. This is now a 10-digit number.

%HOST%

Insert the local hostname

%UPSHOST%

Insert the host of the UPS being monitored (the <system> part of your logging specification, e.g. ups[@host[:port]])

%PID%

Insert the PID of upslog itself

%VAR varname%

Insert the value of variable varname (see NUT developer documentation chapter "Variables" on-line or in the docs/nut-names.txt file in sources of the NUT version you have installed for more details)

The default format string is:

%TIME @Y@m@d @H@M@S% %VAR battery.charge% %VAR input.voltage%
%VAR ups.load% [%VAR ups.status%] %VAR ups.temperature%
%VAR input.frequency%

-N

Prefix %UPSHOST%%t before the format string (whether default or custom). Useful when logging many systems into same target.

Note
This option DOES NOT currently check if you already have %UPSHOST% in the formatting string (e.g. specified explicitly).

-i interval

Wait this many seconds between polls. This defaults to 30 seconds.

If you require tighter timing, consider writing your own logger using the upsclient(3) library.

-d count

Exit after specified amount of updates. Default is 0 for infinite loop (until interrupted otherwise).

-l logfile

Store the results in this file.

You can use - for stdout, but upslog will remain in the foreground by default.

Requires that the -s <system> option is also used for the single-system logging.

Can be used with the -m <tuple>, will be added to the list.

-D

Raise debugging verbosity level by one; upslog will remain in the foreground by default.

-F

upslog will run in the foreground, regardless of logging target.

-B

upslog will run in the background, regardless of logging target or debugging.

-s ups

Monitor this UPS. The format for this option is upsname[@hostname[:port]]. The default hostname is "localhost".

The upsname may be an asterisk * to query UPSes currently served by hostname, and monitor each of them (into the same logging destination).

Requires that the -l <logfile> option is also used for the single-system logging.

Can be used with the -m <tuple>, will be added to the list.

-m tuple

Monitor multiple UPSs (provided several instances of such option).

The format for this option is a tuple of UPS system and log file specification, separated by commas. An example would be:

upsname@hostname:9999,/var/log/nut/cps.log

The upsname may be an asterisk * to query UPSes currently served by hostname, and monitor each of them (into the same logging destination).

Tuples may specify - as the logfile, to emit messages on stdout (e.g. to be collected by the system journal for services).

Use of stdout via tuple-based logging specifications also implies that upslog will remain in the foreground by default.

-u username

If started as root, upslog will setuid(2) to the user id associated with username for security.

If username is not defined, it will use the value that was compiled into the program. This defaults to nobody (if not otherwise configured), which is far from ideal.

COMMON OPTIONS¶

-h

Show the command-line help message.

-V

Show NUT version banner. More details may be available if you also export NUT_DEBUG_LEVEL=1 or greater verbosity level.

-W secs

Set the timeout for initial network connections (by default they are indefinitely non-blocking, or until the system interrupts the attempt). Overrides the optional NUT_DEFAULT_CONNECT_TIMEOUT environment variable.

SERVICE DELAYS¶

The interval value is merely the number given to sleep(3) after running through the format string. Therefore, a query will actually take slightly longer than the interval, depending on the speed of your system.

ON-DEMAND LOGGING¶

Sending a SIGUSR1 to a running upslog process makes it wake from the current sleep and log immediately. This is useful when triggered from a upssched event trigger (e.g. AT ONBATT or AT ONLINE) to ensure that an entry always exists, even if the power goes away for a period of time shorter than that specified by the -i argument.

LOG CO-LOCATION¶

It is possible and safe to specify the same log file (including - for stdout) in several tuples, and it would only be opened or closed once without conflict.

Consider adding %UPSHOST% to your custom formatting string (e.g. by using the -N command-line option), in order to easily differentiate lines corresponding to different systems, when logging them to the same target.

LOG ROTATION¶

upslog writes its PID to upslog.pid, and will reopen the log file if you send it a SIGHUP. This allows it to keep running when the log is rotated by an external program.

CAVEATS¶

Historically this daemon supported logging of data for one UPS system per run (specified by the -s option) into one log file name or stdout (specified by the -l option).

Since NUT v2.8.1 it allowed to log several devices (each logged into its individual destination file or common stdout) as specified by multiple -m tuple options. But the two modes were effectively exclusive of each other (single-UPS options were ignored if tuples are also provided).

Since NUT v2.8.3, the single-UPS options are added to the list of tuples, so both legacy and new options can be reliably used to monitor multiple devices in the same run.

Source file:	upslog.8.en.gz (from nut-client 2.8.3-2)
Source last updated:	2025-07-08T07:13:09Z
Converted to HTML:	2025-07-08T14:57:19Z