Man pages › Compared with Linux and the BSDs

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

On Solnix, df is the illumos df, documented in section 8 and installed at both /usr/bin/df and /usr/sbin/df. Its letters differ sharply from Linux and the BSDs: -t prints totals instead of selecting a file system type, -h scales by 1024 as on Linux, and there is no -i, -H, -T or -B.

The manual pages

Solnix: df(8) 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

A default Solnix system runs the illumos df at /usr/bin/df and /usr/sbin/df. /usr/xpg4/bin/df and /usr/ucb/df are also shipped, but the bundle does not describe how they differ. Unlike the other systems, the Solnix df can also report on unmounted file systems, using -F.

Differences

Compared with	Topic	What differs
all four	`-t` meaning	Solnix df `-t` prints full listings with totals. On Linux, FreeBSD, OpenBSD and NetBSD, `-t` type limits the listing to file systems of that type. Scripts that use df `-t` ext4 or df `-t` nonfs break on Solnix. Source: Solnix df(8) -t; Linux df(1) -t, --type; FreeBSD df(1) -t; OpenBSD df(1) -t; NetBSD df(1) -t
all four	inode reporting (`-i` vs `-e`)	Solnix has no `-i`. Its `-e` prints only the number of files free. Linux, FreeBSD, OpenBSD and NetBSD use `-i` to add or list inode statistics. Source: Solnix df(8) -e and SYNOPSIS; Linux df(1) -i; FreeBSD df(1) -i; OpenBSD df(1) -i; NetBSD df(1) -i
all four	`-P` meaning	Solnix `-P` is documented as the same as `-h` but in 512-byte units. Linux `-P` selects the POSIX output format. OpenBSD `-P` is a stricter format for portable scripts, and NetBSD `-P` has a fixed header and format. FreeBSD `-P` means 512-byte blocks. Source: Solnix df(8) -P; Linux df(1) -P; FreeBSD df(1) -P; OpenBSD df(1) -P; NetBSD df(1) -P
FreeBSD, OpenBSD, NetBSD	`-n` meaning	Solnix `-n` prints only the FSType name (a list of mounted types if no operand is given). On FreeBSD, OpenBSD and NetBSD, `-n` prints previously obtained, possibly stale statistics instead of requesting new ones. Source: Solnix df(8) -n; FreeBSD df(1) -n; OpenBSD df(1) -n; NetBSD df(1) -n
FreeBSD, NetBSD	`-g` meaning	Solnix `-g` prints the entire statvfs(2) structure. FreeBSD `-g` reports in 1 GiB blocks and NetBSD `-g` in gigabytes. NetBSD's own `-G` is described as modelled after the Solaris `-g` option. Source: Solnix df(8) -g; FreeBSD df(1) -g; NetBSD df(1) -g, -G
FreeBSD, NetBSD	`-b` meaning	Solnix `-b` prints the total number of kilobytes free. FreeBSD `-b` and NetBSD `-b` select 512-byte blocks and override BLOCKSIZE. Source: Solnix df(8) -b; FreeBSD df(1) -b; NetBSD df(1) -b
Linux, FreeBSD, NetBSD	`-h` and `-H`	Solnix `-h` scales by 1024 (e.g. 14K, 234M, 2.7G) and is a variant of `-k` that overrides `-b`, `-e`, `-g`, `-k`, `-n`, `-t` and `-V`. It cannot be combined with `-o`. Solnix has no `-H` for powers of 1000, which Linux, FreeBSD and NetBSD provide. Source: Solnix df(8) -h; Linux df(1) -h, -H; FreeBSD df(1) -H; NetBSD df(1) -H
Linux, FreeBSD	filesystem type column and filtering	Solnix has no `-T` to show the file system type and no `-x` to exclude types. Linux has `-T` and `-x`. FreeBSD has `-T`. On Solnix, `-F` FSType selects the type to operate on, and `-n` lists type names. Source: Solnix df(8) -F, -n; Linux df(1) -T, -x; FreeBSD df(1) -T
Linux	block size selection	Linux has `-B` SIZE and reads DF_BLOCK_SIZE, BLOCK_SIZE and BLOCKSIZE. Solnix has no `-B` and its page lists none of these variables. It offers `-k`, `-m` and `-v` for fixed units. Source: Linux df(1) -B, OPTIONS closing paragraph; Solnix df(8) -k, -m, -v, ENVIRONMENT VARIABLES
FreeBSD, OpenBSD, NetBSD	BLOCKSIZE environment variable	FreeBSD, OpenBSD and NetBSD read BLOCKSIZE to choose the unit for block counts. The Solnix page lists only LANG, LC_ALL, LC_CTYPE, LC_MESSAGES and NLSPATH, and does not document BLOCKSIZE. Source: FreeBSD df(1) ENVIRONMENT; OpenBSD df(1) ENVIRONMENT; NetBSD df(1) ENVIRONMENT; Solnix df(8) ENVIRONMENT VARIABLES
all four	unmounted file systems and zones	Solnix df can report on unmounted file systems when given `-F`, and `-V` prints the file-system-specific command lines without running them. `-Z` shows mounts in all visible zones. Linux df cannot show unmounted file systems, and the BSD pages describe mounted file systems only. Source: Solnix df(8) DESCRIPTION, -F, -V, -Z; Linux df(1) DESCRIPTION; FreeBSD df(1) DESCRIPTION; OpenBSD df(1) DESCRIPTION
FreeBSD, NetBSD	grand total	FreeBSD and NetBSD use `-c` for a grand total, and Linux uses `--total`. Solnix has no `-c`. Its `-t` prints full listings with totals. Source: Solnix df(8) -t; FreeBSD df(1) -c; NetBSD df(1) -c; Linux df(1) --total

Standards

POSIX: df is a POSIX.1-2024 utility.
Solnix: ATTRIBUTES: Interface Stability is Standard.
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. OpenBSD provides the traditional BSD -t behaviour, which differs from the X/Open System Interfaces option specification.

Writing portable scripts

Avoid -t, -P, -h, -i and -n in scripts meant to run on Solnix and the other systems. They mean different things or are missing. df -k with a file operand is the common ground.
Do not rely on BLOCKSIZE to set units. The Solnix page does not document it. Pass an explicit unit flag such as -k instead.

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.