Man pages › Compared with Linux and the BSDs

`df(1b)` on Solnix vs Linux and the BSDs

This page documents /usr/ucb/df, the BSD-compatibility df on Solnix, which is not the df that a plain `df` runs. It documents only -a, -i and -t type, with no size-unit, portability or local-only options. Scripts written for Linux or BSD df flags such as -h, -k, -P or -l will not match this page.

The manual pages

Solnix: df(1b) from pkgs.solnix.illumos-world-man · illumos.org
Linux: df(1) coreutils-full-9.11
FreeBSD: df(1) 15.1-RELEASE
OpenBSD: df(1) 8.0
NetBSD: df(1) 11.0
Standard: POSIX.1-2024 (IEEE Std 1003.1-2024), df

What Solnix runs

The page df(1b) describes /usr/ucb/df. A default Solnix system puts the illumos /usr/bin/df and /usr/sbin/df on PATH, and also ships /usr/xpg4/bin/df. The bundle contains no text for those three, so this page cannot say how their options differ from /usr/ucb/df. Run /usr/ucb/df explicitly if you need the behaviour described here.

Differences

Compared with	Topic	What differs
all four	which df this page covers	The Solnix page covers `/usr/ucb/df` only. The df found on PATH by default is `/usr/bin/df`, whose options this bundle does not document. Do not assume a plain `df` behaves as described here. Source: Solnix df(1b) SYNOPSIS (/usr/ucb/df); bundle header (default on PATH is /usr/bin/df, /usr/sbin/df)
all four	size units and human-readable output	Solnix `/usr/ucb/df` documents no option to choose units: no `-k`, `-h`, `-H`, `-m`, `-g` or `-B`. It does not state the default block size, nor any BLOCKSIZE variable. Linux defaults to 1K blocks; FreeBSD, OpenBSD and NetBSD to 512-byte blocks. Source: Solnix df(1b) OPTIONS; Linux df(1) DESCRIPTION, -B, -h, -k; FreeBSD df(1) -b, -g, -h, -k, -m, ENVIRONMENT; OpenBSD df(1) -h, -k; NetBSD df(1) -k, -m, -g
all four	portable output (`-P`)	Solnix `/usr/ucb/df` has no `-P`. Linux `-P` selects the POSIX output format. OpenBSD `-P` is a stricter parseable format that ignores BLOCKSIZE. NetBSD `-P` documents an exact header and line format. FreeBSD `-P` means 512-byte blocks, the same as `-b`. Source: Solnix df(1b) OPTIONS; Linux df(1) -P; OpenBSD df(1) -P; NetBSD df(1) -P; FreeBSD df(1) -P, BUGS
FreeBSD, OpenBSD, NetBSD	`-t` type syntax	Solnix `-t` type takes a single type, for example nfs or ufs. FreeBSD, OpenBSD and NetBSD accept a comma-separated list, and a 'no' prefix excludes types. The Solnix page documents neither. Source: Solnix df(1b) -t; FreeBSD df(1) -t; OpenBSD df(1) -t; NetBSD df(1) -t
Linux	excluding file system types	Solnix `/usr/ucb/df` has no exclusion option. Linux `-x`, `--exclude-type=TYPE` lists file systems not of that type, and `-t`, `--type=TYPE` limits the listing to one type. Source: Solnix df(1b) OPTIONS; Linux df(1) -t, -x
Linux, FreeBSD, NetBSD	`-a` meaning	Solnix `-a` adds file systems with zero total blocks, such as the auto-mounter. Linux `-a` adds pseudo, duplicate and inaccessible file systems. FreeBSD and NetBSD `-a` adds mount points flagged MNT_IGNORE. OpenBSD df has no `-a`. Source: Solnix df(1b) -a; Linux df(1) -a; FreeBSD df(1) -a; NetBSD df(1) -a; OpenBSD df(1) SYNOPSIS
all four	`-i` inode report	Solnix `-i` reports used and free inodes and prints '*' where no information is available. Linux `-i` lists inode information instead of block usage. FreeBSD prints '-' in place of the usage percentage when a file system has no inodes. The Solnix page does not say whether block columns remain. Source: Solnix df(1b) -i; Linux df(1) -i; FreeBSD df(1) -i; OpenBSD df(1) -i; NetBSD df(1) -i
all four	local-only listing (`-l`)	Solnix `/usr/ucb/df` documents no `-l` to limit output to local file systems. Linux, FreeBSD, OpenBSD and NetBSD all provide `-l`. Source: Solnix df(1b) OPTIONS; Linux df(1) -l; FreeBSD df(1) -l; OpenBSD df(1) -l; NetBSD df(1) -l
Linux, FreeBSD	file system type column (`-T`)	Solnix `/usr/ucb/df` has no `-T` to print the file system type. Linux `-T`, `--print-type` and FreeBSD `-T` add the type column. NetBSD and OpenBSD df have no `-T`. Source: Solnix df(1b) OPTIONS; Linux df(1) -T; FreeBSD df(1) -T; OpenBSD df(1) SYNOPSIS; NetBSD df(1) SYNOPSIS
FreeBSD, OpenBSD, NetBSD	stale statistics (`-n`)	FreeBSD, OpenBSD and NetBSD `-n` prints previously obtained statistics without querying file systems, to avoid delays on hung file systems. Solnix `/usr/ucb/df` documents no such option. Source: Solnix df(1b) OPTIONS; FreeBSD df(1) -n; OpenBSD df(1) -n; NetBSD df(1) -n
all four	exit status	The Solnix page has no EXIT STATUS section. OpenBSD documents exit 0 on success and >0 on error. The Linux, FreeBSD and NetBSD pages in the bundle do not give a status either. Source: Solnix df(1b) (no EXIT STATUS); OpenBSD df(1) EXIT STATUS

Standards

POSIX: df is a POSIX.1-2024 utility.
Solnix: The df(1b) page has no STANDARDS section, so it states no conformance.
FreeBSD: With the exception of most options, df conforms to IEEE Std 1003.1-2004 (“POSIX.1”), which defines only the -k, -P and -t options.
OpenBSD: df is compliant with the IEEE Std 1003.1-2008 (“POSIX.1”) specification. The flags [-hiln] and BLOCKSIZE are extensions. The traditional BSD -t behaviour differs from the X/Open System Interfaces option specification.

Writing portable scripts

Use only -k, -P and -t in portable scripts, since FreeBSD says POSIX defines only those. Even then, -t differs: Solnix /usr/ucb/df takes one type, while the BSDs take a list.
Do not rely on `df` meaning /usr/ucb/df on Solnix. Call /usr/ucb/df explicitly if you need this page's behaviour, or test the option you need on the df on PATH.

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.