rwho(1) on Solnix vs Linux and the BSDs

On Solnix, rwho is the illumos rwho at /usr/bin/rwho. It shows users on other machines whose rwhod broadcasts it has received. The main difference from FreeBSD and NetBSD is the down-host timeout: 5 minutes on Solnix, 11 minutes on the BSDs. NetBSD also has -H and -q, which Solnix lacks.

What Solnix runs

A default Solnix system runs the illumos rwho at /usr/bin/rwho. /usr/ucb/rwho is also shipped, but the bundle does not describe it. The daemon is in.rwhod(8), which must be enabled for rwho to return useful results. The page also says /var/spool/rwho must exist on the host that runs rwho.

Differences

Compared withTopicWhat differs
FreeBSD, NetBSDhost-down timeoutSolnix rwho treats a machine as down after 5 minutes without a report. FreeBSD and NetBSD use 11 minutes. A host that is missed briefly can drop off the Solnix listing sooner.
Source: Solnix rwho(1) DESCRIPTION; FreeBSD rwho(1) DESCRIPTION; NetBSD rwho(1) DESCRIPTION
NetBSD-H column headingsNetBSD rwho -H writes column headings above the output. Solnix rwho has only -a, so -H is not documented there.
Source: NetBSD rwho(1) SYNOPSIS, -H; Solnix rwho(1) SYNOPSIS
NetBSD-q quick modeNetBSD rwho -q lists only user names and the number of users logged on, and ignores other options. Solnix has no -q.
Source: NetBSD rwho(1) -q; Solnix rwho(1) OPTIONS
FreeBSD, NetBSDdaemon name and requirementsThe Solnix page names the daemon in.rwhod(8) and says it must be enabled. It also says /var/spool/rwho must exist on the host running rwho. The FreeBSD and NetBSD pages list rwhod(8) under SEE ALSO and do not state either requirement.
Source: Solnix rwho(1) NOTES, SEE ALSO; FreeBSD rwho(1) SEE ALSO; NetBSD rwho(1) SEE ALSO
FreeBSD, NetBSDnetwork limits documentedThe Solnix page says rwho does not work through gateways. It also says bandwidth use grows with the number of hosts, to a prohibitive cost on large networks. FreeBSD and NetBSD only say it is unwieldy on large local nets.
Source: Solnix rwho(1) NOTES; FreeBSD rwho(1) BUGS; NetBSD rwho(1) BUGS
FreeBSD, NetBSD-a behaviour-a means the same on all three: include users idle for an hour or more, who are otherwise omitted. This is not a difference.
Source: Solnix rwho(1) -a; FreeBSD rwho(1) -a; NetBSD rwho(1) -a

Standards

  • POSIX: rwho is not a POSIX.1-2024 utility.
  • FreeBSD: HISTORY: the rwho command appeared in 4.3BSD.
  • NetBSD: HISTORY: the rwho command appeared in 4.3BSD.

Writing portable scripts

  • Use only rwho and rwho -a in portable scripts. -H and -q exist only on NetBSD.
  • Do not rely on a host being absent from the output to mean it is down. The timeout is 5 minutes on Solnix and 11 minutes on FreeBSD and NetBSD.

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.