LSCLOCKS(1)                      User Commands                     LSCLOCKS(1)

NAME
       lsclocks - display system clocks

SYNOPSIS
       lsclocks [option]

DESCRIPTION
       lsclocks is a simple command to display system clocks.

       It allows to display information like current time and resolution of
       clocks.  Different kinds of clocks are supported.

       o   POSIX clocks: CLOCK_MONOTONIC, CLOCK_REALTIME, CLOCK_BOOTTIME, etc.

       o   CPU clocks: clock_getcpuclockid(3).

       o   PTP clocks: /dev/ptp0.

       o   RTC clocks: /dev/rtc0.

       o   Auxiliary clocks: CLOCK_AUX0, CLOCK_AUX1, etc.

OPTIONS
       -J, --json
           Use JSON output format.

       -n, --noheadings
           Don't print headings.

       -o, --output list
           Specify which output columns to print. See the OUTPUT COLUMNS
           section for details of available columns.

       --output-all
           Output all columns.

       -r, --raw
           Use raw output format.

       -t, --time clock
           Show current time of one specific clock.

       --no-discover-dynamic
           Do not try to discover dynamic clocks.

       -d, --dynamic-clock path
           Also display specified dynamic clock.  Can be specified multiple
           times.

       --no-discover-rtc
           Do not try to discover RTCs.

       -x, --rtc path
           Also display specified RTC.  Can be specified multiple times.

       -c, --cpu-clock pid
           Also display CPU clock of specified process.  Can be specified
           multiple times.

       -h, --help
           Display help text and exit.

       -V, --version
           Display version and exit.

ENVIRONMENT
       LSCLOCKS_COLUMNS=
           Specifies a comma-separated list of output columns to print. All
           columns listed in OUTPUT COLUMNS can be used.

       LIBSMARTCOLS_DEBUG=all
           enables libsmartcols debug output.

       LIBSMARTCOLS_DEBUG_PADDING=on
           use visible padding characters.

       LIBSMARTCOLS_JSON=compact|lines
           Controls JSON output format when using --json. Supported values are
           compact for JSON output with minimal whitespace, and lines for JSON
           Lines format (one JSON object per line). If unset or set to any
           other value, pretty-printed JSON is used.

OUTPUT COLUMNS
       Each column has a type. Types are surround by < and >.

       TYPE <string>
           Clock type.

       ID <number>
           Numeric clock ID.

       CLOCK <string>
           Name in the form CLOCK_

       NAME <string>
           Shorter, easier to read name.

       TIME <number>
           Current clock timestamp as returned by clock_gettime(2).

       ISO_TIME <string>
           ISO8601 formatted version of TIME.

       RESOL_RAW <number>
           Clock resolution as returned by clock_getres(2).

       RESOL <number>
           Human readable version of RESOL_RAW.

       REL_TIME <string>
           TIME time formatted as time range.

       NS_OFFSET <number>
           Offset of the current namespace to the parent namespace as read
           from /proc/self/timens_offsets.

AUTHORS
       Thomas Weissschuh <thomas@t-8ch.de>

SEE ALSO
       clock_getres(2) clock_gettime(2)

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

AVAILABILITY
       The lsclocks 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/>.

util-linux 2.42.3                 2026-09-02                       LSCLOCKS(1)