Man pages › Compared with Linux and the BSDs

`dmesg(8)` on Solnix vs Linux and the BSDs

On Solnix, dmesg is the illumos dmesg, installed at both /usr/bin/dmesg and /usr/sbin/dmesg. It takes no options and prints the system buffer to standard output. Linux, FreeBSD, OpenBSD and NetBSD all document options (clearing, filtering, timestamps, core files) that the Solnix page does not.

The manual pages

Solnix: dmesg(8) from pkgs.solnix.illumos-world-man · illumos.org
Linux: dmesg(1) util-linux-2.42.3
FreeBSD: dmesg(8) 15.1-RELEASE
OpenBSD: dmesg(8) 8.0
NetBSD: dmesg(8) 11.0

What Solnix runs

A default Solnix system runs the illumos dmesg at /usr/bin/dmesg and /usr/sbin/dmesg. No other variants are shipped. The page lists no options. It says dmesg is made obsolete by syslogd(8) for maintaining the system error log.

Differences

Compared with	Topic	What differs
all four	options	The Solnix SYNOPSIS lists no options for either path. Linux, FreeBSD, OpenBSD and NetBSD all document options. A script that passes flags to dmesg on those systems has no documented Solnix equivalent. Source: Solnix dmesg(8) SYNOPSIS; Linux dmesg(1) OPTIONS; FreeBSD dmesg(8) SYNOPSIS; OpenBSD dmesg(8) SYNOPSIS; NetBSD dmesg(8) SYNOPSIS
Linux, FreeBSD	clearing the buffer	Linux dmesg `-C` clears the ring buffer and `-c` prints it and then clears it. FreeBSD dmesg `-c` clears the buffer after printing. The Solnix page documents no way to clear the buffer. Source: Linux dmesg(1) -C, -c; FreeBSD dmesg(8) -c; Solnix dmesg(8) DESCRIPTION
Linux	`-c` meaning and `-C`	Linux `-c` is `--read-clear` (print, then clear). Linux `-C` only clears. Neither flag is documented on Solnix, so do not rely on them there. Source: Linux dmesg(1) -C, --clear; -c, --read-clear; Solnix dmesg(8) SYNOPSIS
Linux, NetBSD	timestamps	Linux has `-T` (human-readable time), `-t` (no timestamps), `-e`, `-d` and `--time-format`. NetBSD has `-T` (ctime form; repeated, ISO 8601 duration), `-t` (no timestamps) and `-d` (deltas). The Solnix page documents no timestamp options or timestamp format. Source: Linux dmesg(1) -T, -t, -d, -e, --time-format; NetBSD dmesg(8) -T, -t, -d; Solnix dmesg(8) SYNOPSIS
Linux	filtering by level or facility	Linux dmesg can restrict output with `-l`/-`-level` and `-f`/-`-facility`, and by time with `--since` and `--until`. The Solnix page documents no filtering; dmesg prints what is in the buffer. Source: Linux dmesg(1) -l, -f, --since, --until; Solnix dmesg(8) DESCRIPTION
Linux	console and output control	Linux dmesg can set the console message level (`-n`), turn console printing off (`-D`) or on (`-E`), print JSON (`-J`) and read from a file (`-F`, `-K`). None of these is documented for Solnix dmesg. Source: Linux dmesg(1) -n, -D, -E, -J, -F, -K; Solnix dmesg(8) SYNOPSIS
FreeBSD, OpenBSD, NetBSD	reading from a core file	FreeBSD, OpenBSD and NetBSD accept `-M` core and `-N` system to read the message buffer from a core file and a named kernel image. The Solnix page documents neither option. Source: FreeBSD dmesg(8) -M, -N; OpenBSD dmesg(8) -M, -N; NetBSD dmesg(8) -M, -N; Solnix dmesg(8) SYNOPSIS
FreeBSD	`-a` flag	FreeBSD `-a` also shows syslog records and /dev/console output in the buffer. The Solnix page does not document `-a` or any equivalent. Source: FreeBSD dmesg(8) -a; Solnix dmesg(8) SYNOPSIS
OpenBSD	console buffer (`-s`)	OpenBSD `-s` displays the console message buffer, which shows rc(8) startup messages, and is limited to the superuser. The Solnix page documents no such option. Source: OpenBSD dmesg(8) -s; Solnix dmesg(8) SYNOPSIS
all four	role versus syslogd	The Solnix page says dmesg is made obsolete by syslogd(8) for maintaining the system error log. The other pages describe dmesg as the way to view the kernel or system buffer and only refer to syslogd in SEE ALSO or in the Linux `-n` text. Source: Solnix dmesg(8) DESCRIPTION; Linux dmesg(1) DESCRIPTION; FreeBSD dmesg(8) SEE ALSO; OpenBSD dmesg(8) SEE ALSO; NetBSD dmesg(8) SEE ALSO

Standards

POSIX: dmesg is not a POSIX.1-2024 utility.
Solnix: The page's SEE ALSO points to attributes(7), but the trimmed text in the bundle shows no ATTRIBUTES or interface stability section.

Writing portable scripts

Run plain dmesg with no options in portable scripts. That is the only form the Solnix page documents. Filter the output with grep or tail instead of Linux-only flags such as --level.
Do not assume timestamps in the output. Linux -t, NetBSD -t and -T control them, and the Solnix page documents no timestamp options.

Every difference here is taken from the manual pages linked above: Solnix's published page, Linux (man-pages and the GNU and util-linux manuals), FreeBSD, OpenBSD and NetBSD. Each row names its source. Where a manual is silent, this page is too. Compiled 2026-10-26. Found a mistake? Mail hackers@lists.solnix.io.