Man pages › Compared with Linux and the BSDs

`ssh-agent(1)` on Solnix vs Linux and the BSDs

On Solnix, ssh-agent is the OpenSSH agent from pkgs.solnix.openssh, and it is what a default system runs. Its option set matches NetBSD's, and Linux's apart from -V. FreeBSD differs most: its page documents a different default socket location, -x, and no -T, -U or -u.

The manual pages

Solnix: ssh-agent(1) from pkgs.solnix.openssh
Linux: ssh-agent(1) openssh-10.5p1
FreeBSD: ssh-agent(1) 15.1-RELEASE
OpenBSD: ssh-agent(1) 8.0
NetBSD: ssh-agent(1) 11.0

What Solnix runs

A default Solnix system runs the OpenSSH ssh-agent from pkgs.solnix.openssh, which is part of the base system packages. No other variants are shipped. The Solnix page documents no -V, -x or -A options.

Differences

Compared with	Topic	What differs
FreeBSD	default socket location	Solnix, like Linux, OpenBSD and NetBSD, creates the socket at a random path matching $HOME/.ssh/agent/s.*. The FreeBSD page gives the default as $TMPDIR/ssh-XXXXXXXXXX/agent.<ppid>. A script that assumes the socket is under /tmp or $TMPDIR may break on Solnix. Source: Solnix ssh-agent(1) -a; FreeBSD ssh-agent(1) -a
FreeBSD	`-T`, `-U`, `-u` missing on FreeBSD	Solnix accepts `-T` (socket in a $TMPDIR/ssh-XXXXXXXXXX subdirectory), `-U` (do not clean up stale sockets) and `-u` (clean up stale sockets and exit). The FreeBSD page lists none of these in its synopsis or options. Source: Solnix ssh-agent(1) SYNOPSIS, -T, -U, -u; FreeBSD ssh-agent(1) SYNOPSIS
FreeBSD	`-x`	FreeBSD ssh-agent has `-x`, which exits after the last client has disconnected. Solnix has no `-x`. Its agent keeps running until it is killed with `-k`, exits because the command given on its command line ends, or is stopped by `-u`. Source: FreeBSD ssh-agent(1) -x; Solnix ssh-agent(1) SYNOPSIS and options
Linux, OpenBSD	`-V`	Linux and OpenBSD ssh-agent have `-V`, which prints the version number and exits. The Solnix page documents no `-V`, so a script should not use it to detect the version. Source: Linux ssh-agent(1) -V; OpenBSD ssh-agent(1) -V; Solnix ssh-agent(1) SYNOPSIS
OpenBSD	`-A` directory	OpenBSD ssh-agent has `-A` socket_path to choose the directory for the socket, with user: and shared: prefixes. In OpenBSD, `-T`, `-A` and `-a` are alternatives. Solnix has no ssh-agent `-A`. In ssh(1), `-A` is the agent-forwarding option. Source: OpenBSD ssh-agent(1) SYNOPSIS, -A; Solnix ssh-agent(1) SYNOPSIS
OpenBSD, NetBSD	socket activation	The Solnix page describes a third setup method, socket activation from a supervising process such as systemd. It is used with `-d` or `-D`, no `-a`, and LISTEN_FDS and LISTEN_PID set. The OpenBSD and NetBSD pages describe only two methods. Source: Solnix ssh-agent(1) DESCRIPTION (third way); OpenBSD ssh-agent(1) DESCRIPTION (two main ways); NetBSD ssh-agent(1) DESCRIPTION (two main ways)
Linux, OpenBSD, NetBSD	`-P` default provider path	The Solnix `-P` default is printed as "usr/lib/,`/usr/local/lib`/", with no leading slash on the first entry, and the FreeBSD page prints the same. Linux prints "`/usr/lib`/,`/usr/local/lib`/". OpenBSD and NetBSD print "`/usr/lib/`,`/usr/local/lib/`". Set `-P` explicitly if you rely on PKCS#11 or FIDO libraries. Source: Solnix ssh-agent(1) -P; Linux ssh-agent(1) -P; OpenBSD ssh-agent(1) -P; NetBSD ssh-agent(1) -P
Linux	same program as Linux	Apart from `-V` and the `-P` default path text, the Solnix page matches the Linux page (openssh-10.5p1) in synopsis, options, shell selection, lifetime and environment variables. Source: Solnix ssh-agent(1) SYNOPSIS, options; Linux ssh-agent(1) SYNOPSIS, options
NetBSD	same options as NetBSD	NetBSD's synopsis and options (`-DdTU`, `-a`, `-E`, `-O`, `-P`, `-t`, `-k`, `-u`) match Solnix's. The differences are only the missing socket-activation paragraph and the `-P` default path. Source: NetBSD ssh-agent(1) SYNOPSIS; Solnix ssh-agent(1) SYNOPSIS

Standards

POSIX: ssh-agent is not a POSIX.1-2024 utility.

Writing portable scripts

Do not hard-code the agent socket path. Read SSH_AUTH_SOCK, because the default location is $HOME/.ssh/agent/s.* on Solnix but $TMPDIR/ssh-XXXXXXXXXX/agent.<ppid> on FreeBSD.
Avoid -V, -x and -A in scripts that must run on all four systems. Each exists on only some of them. Use -k to stop an agent.

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.