Man pages › Compared with Linux and the BSDs

`unexpand(1)` on Solnix vs Linux and the BSDs

On a default Solnix system, unexpand is the illumos /usr/bin/unexpand, which takes only -a and -t tablist. The published Solnix page describes the GNU coreutils unexpand from pkgs.solnix.coreutils, which adds long options, --first-only and extended tab lists. Scripts written for GNU unexpand can fail on the default command.

The manual pages

Solnix: unexpand(1) from pkgs.solnix.coreutils
Linux: unexpand(1) coreutils-full-9.11
FreeBSD: unexpand(1) 15.1-RELEASE
NetBSD: unexpand(1) 11.0
Standard: POSIX.1-2024 (IEEE Std 1003.1-2024), unexpand

What Solnix runs

The published page (pkgs.solnix.coreutils) is GNU coreutils 9.7 unexpand, but the command on PATH by default is the illumos /usr/bin/unexpand. No other illumos variants are shipped. The illumos page documents expand and unexpand together and lists only -a and -t tablist for unexpand. To get the GNU behaviour, add pkgs.solnix.coreutils; the bundle does not say where that copy is installed.

Differences

Compared with	Topic	What differs
Linux	same program as GNU only in the package	The GNU unexpand in pkgs.solnix.coreutils is the same program as Linux unexpand: the options and tab-list syntax are identical in the two pages. The default illumos `/usr/bin/unexpand` is not that program. Source: Solnix unexpand(1) (coreutils) DESCRIPTION; Linux unexpand(1) DESCRIPTION; header line on default PATH
Linux	long options and `--first-only`	The default Solnix unexpand has only `-a` and `-t`. It documents no `--all`, `--tabs`, `--first-only`, `--help` or `--version`. GNU unexpand, on Linux and in pkgs.solnix.coreutils, has all of them. Source: Solnix default (illumos) unexpand(1) SYNOPSIS, OPTIONS; Linux unexpand(1) -a/--all, --first-only, -t/--tabs, --help, --version
Linux	`-t` implies `-a`, and how to undo it	Both GNU and illumos say `-t` makes conversion apply to all blanks, not just leading ones. GNU adds `--first-only`, which overrides `-a` and restores leading-only conversion. The illumos page offers no way to combine `-t` with leading-only conversion. Source: Linux unexpand(1) -t, --tabs=N (enables -a), --first-only; Solnix default (illumos) unexpand(1) -t
Linux	tab list syntax	illumos `-t` takes one argument of positive integers in strictly ascending order, separated by blanks or commas. GNU takes a comma-separated list and adds a '/' prefix (tab size after the last stop) and a '+' prefix (stops relative to the last stop). Source: Solnix default (illumos) unexpand(1) -t; Linux unexpand(1) -t, --tabs=LIST
Linux	stops beyond the last tab position	On illumos, with a multiple-stop list, no space-to-tab conversion happens beyond the last stop. GNU lets you set a tab size after the last stop with a '/' prefix. The GNU page does not say what happens without the prefix. Source: Solnix default (illumos) unexpand(1) -t; Linux unexpand(1) -t, --tabs=LIST
FreeBSD, NetBSD	`-t` with `-a`	The illumos page says that when `-t` is given, `-a` is ignored and conversion is not limited to leading blanks. The FreeBSD and NetBSD pages do not say this. FreeBSD's synopsis shows `-a` and `-t` as alternatives ([`-a` \| `-t` ...]). Source: Solnix default (illumos) unexpand(1) -t; FreeBSD unexpand(1) SYNOPSIS, -a, -t; NetBSD unexpand(1) SYNOPSIS, -a
NetBSD	`-t` documented for unexpand	The NetBSD synopsis shows unexpand [`-a`] [`-t` tab1,tab2,...,tabn], but its only documented option for unexpand is `-a`. The tab-stop text describes expand. illumos, FreeBSD and GNU document `-t` for unexpand. Source: NetBSD unexpand(1) SYNOPSIS, DESCRIPTION; FreeBSD unexpand(1) -t; Solnix default (illumos) unexpand(1) -t
Linux	environment variables	The illumos page lists LANG, LC_ALL, LC_CTYPE, LC_MESSAGES and NLSPATH as affecting expand and unexpand. The GNU page in the bundle lists none. Source: Solnix default (illumos) unexpand(1) ENVIRONMENT VARIABLES; Linux unexpand(1)
FreeBSD	environment variables	FreeBSD documents LANG, LC_ALL and LC_CTYPE only. illumos also lists LC_MESSAGES and NLSPATH. Source: FreeBSD unexpand(1) ENVIRONMENT; Solnix default (illumos) unexpand(1) ENVIRONMENT VARIABLES
Linux, NetBSD	exit status documented	illumos and FreeBSD document exit 0 on success and >0 on error. The GNU page and the NetBSD page in the bundle have no EXIT STATUS section. Source: Solnix default (illumos) unexpand(1) EXIT STATUS; FreeBSD unexpand(1) EXIT STATUS; Linux unexpand(1); NetBSD unexpand(1)
FreeBSD, NetBSD	one page for expand and unexpand	illumos, FreeBSD and NetBSD document expand and unexpand in one page. The GNU page covers unexpand alone and refers to expand(1) under SEE ALSO. Source: Solnix default (illumos) unexpand(1) NAME; FreeBSD unexpand(1) NAME; NetBSD unexpand(1) NAME; Solnix unexpand(1) (coreutils) SEE ALSO

Standards

POSIX: unexpand is a POSIX.1-2024 utility.
Solnix: The illumos page lists Interface Stability: Standard, and CSI: enabled.
FreeBSD: The expand and unexpand utilities conform to IEEE Std 1003.1-2001 (“POSIX.1”).
NetBSD: The NetBSD page in the bundle has no STANDARDS section.
Linux: The Linux page in the bundle has no STANDARDS section.

Writing portable scripts

Use only -a and -t with a single number or a comma-separated list. Those work on the illumos command and are documented on FreeBSD and GNU; the NetBSD page documents only -a for unexpand.
Avoid --all, --tabs and --first-only in portable scripts: the default Solnix unexpand does not document them, and neither do the BSD pages.
Do not rely on a bare -t leaving trailing blanks alone. On illumos and GNU it converts all blanks. FreeBSD and NetBSD do not say.

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.