uptime(1) on Solnix vs Linux and the BSDs
On Solnix, uptime is the illumos /usr/bin/uptime. It takes no options or arguments, so the Linux FILE argument and the FreeBSD --libxo option do not exist. Its documented output lists load averages but not the number of users.
The manual pages
What Solnix runs
A default Solnix system runs the illumos uptime at /usr/bin/uptime. /usr/ucb/uptime is also shipped, but the bundle does not describe it. The page says who -b gives the last boot time.
Differences
| Compared with | Topic | What differs |
|---|---|---|
| Linux | FILE argument | Linux uptime accepts an optional FILE and reads /var/run/utmp by default (/var/log/wtmp is common). The Solnix SYNOPSIS is only 'uptime', with no file argument.Source: Linux uptime(1) SYNOPSIS and DESCRIPTION; Solnix uptime(1) SYNOPSIS |
| Linux | options | Linux uptime documents --help and --version. The Solnix page documents no options at all.Source: Linux uptime(1) --help, --version; Solnix uptime(1) SYNOPSIS |
| FreeBSD | --libxo | FreeBSD uptime accepts --libxo for machine-readable output. The Solnix page documents no such option, and its output is the single text line described in DESCRIPTION.Source: FreeBSD uptime(1) SYNOPSIS, --libxo; Solnix uptime(1) SYNOPSIS |
| all four | user count in output | Linux, FreeBSD, OpenBSD and NetBSD all document the number of users in the output. The Solnix DESCRIPTION lists the time, the uptime and the 1, 5 and 15 minute load averages, and does not mention users. A script parsing the user count may fail. Source: Solnix uptime(1) DESCRIPTION; Linux, FreeBSD, OpenBSD, NetBSD uptime(1) DESCRIPTION |
| Linux | load average definition | Linux says processes in uninterruptible sleep count toward the load average. The Solnix page describes the figure as jobs in the run queue and says nothing about uninterruptible sleep. Source: Linux uptime(1) DESCRIPTION; Solnix uptime(1) DESCRIPTION |
| NetBSD | load average source | NetBSD says the load average comes from getloadavg(3). The Solnix page does not say where it gets the figure. Source: NetBSD uptime(1) DESCRIPTION; Solnix uptime(1) DESCRIPTION |
| FreeBSD, OpenBSD, NetBSD | relation to w(1) | Solnix and OpenBSD say uptime output is the first line of w(1). NetBSD says it is a subset of what w(1) shows. FreeBSD only lists w(1) under SEE ALSO. Source: Solnix uptime(1) DESCRIPTION; OpenBSD uptime(1) DESCRIPTION; NetBSD uptime(1) DESCRIPTION; FreeBSD uptime(1) SEE ALSO |
| all four | last boot time | The Solnix page points to who -b for the time of the last boot. The other four pages do not mention this.Source: Solnix uptime(1) NOTES |
Standards
- POSIX: uptime is not a POSIX.1-2024 utility.
- FreeBSD: HISTORY: the uptime command appeared in 3.0BSD.
- OpenBSD: HISTORY: the uptime command appeared in 3.0BSD.
- NetBSD: HISTORY: the uptime command appeared in 3.0BSD.
Writing portable scripts
- Call uptime with no arguments and do not parse the user count, since the Solnix page does not document it. For the load averages, take the last three fields.
- Do not pass FILE,
--libxoor--version. Use who-bon Solnix for the boot time.
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.