Custom tab completions in oksh


A chat with @zoomosis made me realise that I never talked about oksh’s tab completion, which is half the reason I use and spruik it as a daily driver shell.

For a recap, I moved to oksh on my Macs and BSD boxes so I could keep roughly the same .kshrc config on each machine I own, even my ancient nostalgia boxes. FreeBSD notably doesn’t include a Kornshell, but macOS and NetBSD do. oksh adds a couple of nice features, while still being fast and lightweight.

oksh’s tab completion is the other reason. Using set statements you can define tab completions for commands you specify. I like to keep these in a separate file, and reference it in my .kshrc:

[ -f ~/.oksh_completions ] && . ~/.oksh_completions

The syntax is simple. Here are some common FreeBSD commands:

set -A complete_geli -- attach backup configure detach
set -A complete_iocage -- create destroy fetch get list rename restart set start stop
set -A complete_pkg -- clean info install lock search unlock update upgrade
set -A complete_pkgin -- autoremove avail install full-upgrade pkg-info remove search update
set -A complete_zfs -- clone create list receive send set snapshot
set -A complete_zpool -- create export import scrub set

Because it’s a shell script, you could do this for SSH hosts:

_SSH_HOSTS=$(awk '/^Host/{ print $2 }' ~/.ssh/config)
set -A complete_mosh -- $_SSH_HOSTS
set -A complete_scp -- $_SSH_HOSTS
set -A complete_ssh -- $_SSH_HOSTS

And for services:

_SERVICES=$(ls -1 /etc/rc.d/)
case `uname` in
        _SERVICES="$_SERVICES $(ls -1 /usr/local/etc/rc.d/)"

There’s a lot you could configure here, and I’ve probably only scratched the surface.

Author bio and support


Ruben Schade is a technical writer and IaaS engineer in Sydney, Australia who refers to himself in the third person in bios. Wait, not BIOS… my brain should be EFI by now.

The site is powered by Hugo, FreeBSD, and OpenZFS on OrionVM, everyone’s favourite cloud infrastructure provider.

You can leave me a comment by contacting me, and I might publish your thoughts. Please read the FAQs first though.

If you found this post helpful or entertaining, you can shout me a coffee or buy some silly merch. Thanks!