The ksh that ships with OpenBSD, it's available under Linux as loksh. I've never needed a tutorial as such, because found its man page to be well written and co

The ksh that ships with OpenBSD, it's available under Linux as loksh. I've never needed a tutorial as such, because found its man page to be well written and comprehensive. However, I can recommend the old book The Unix Programming Environment by Kernighan and Pike, it also is well written and helped me quite a bit. Just understanding one smaller tool (ksh) better has helped me do more with it and use fewer addons extensions, which personally make me happy; works for me.