tac(1) on Solnix vs Linux and the BSDs
tac is not in the Solnix base system. Install pkgs.solnix.coreutils to get GNU coreutils tac, which is the same program as Linux tac and takes -b, -r and -s. NetBSD tac takes no options, only file names.
The manual pages
What Solnix runs
Not installed by default: add pkgs.solnix.coreutils. The bundle lists no illumos variant of tac. The Solnix page is the GNU coreutils 9.7 page.
Differences
| Compared with | Topic | What differs |
|---|---|---|
| Linux | same program | The Solnix page and the Linux page are the same GNU coreutils tac. They have the same synopsis and the same options: -b, -r, -s, --help and --version. The Linux page adds one note about buffering that the Solnix page lacks.Source: Solnix tac(1) SYNOPSIS, DESCRIPTION; Linux tac(1) SYNOPSIS, DESCRIPTION |
| NetBSD | options | NetBSD tac takes no options. Its synopsis is tac [file ...], and the page says it does not support any of the options of GNU tac. Solnix tac accepts -b, -r and -s.Source: NetBSD tac(1) SYNOPSIS, COMPATIBILITY; Solnix tac(1) SYNOPSIS, -b, -r, -s |
| NetBSD | custom separator | Solnix tac -s STRING splits the input on STRING instead of newline, and -r treats the separator as a regular expression. NetBSD tac works only in reverse line order.Source: Solnix tac(1) -s, -r; NetBSD tac(1) DESCRIPTION |
| Linux | temporary files | The Linux page says non-seekable input is buffered to $TMPDIR, defaulting to /tmp. The Solnix page does not say this, though it is the same GNU tac. Source: Linux tac(1) DESCRIPTION (last paragraph); Solnix tac(1) DESCRIPTION |
| NetBSD | exit status | The NetBSD page documents exit 0 on success and >0 on error. The Solnix and Linux pages have no exit status section. Source: NetBSD tac(1) EXIT STATUS; Solnix tac(1); Linux tac(1) |
| FreeBSD, OpenBSD | no counterpart page | The bundle has no FreeBSD or OpenBSD tac page. The manual does not say whether those systems ship tac. Source: bundle header (counterparts: linux, netbsd only) |
Standards
- POSIX: tac is not a POSIX.1-2024 utility.
Writing portable scripts
- Do not use
-b,-ror-sif the script must run on NetBSD, where tac takes only file names. Plain tac [file ...] works on the Solnix, Linux and NetBSD pages. - On Solnix, install pkgs.solnix.coreutils before relying on tac, because it is not in the base system.
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.