document updated 11 years ago, on Oct 12, 2013

To find out what version of Ksh you have installed on your machine:

Type this, followed by enter:

set -o vi

And then press these keys:

It will display something like:

Version M-11/16/88i                 ⇒ KSH-88
Version M-12/28/93                  ⇒ KSH-93
@(#)PD KSH v5.2.14 99/07/13.2       ⇒ PD-KSH

	builtin 2>&1 \| wc -l	builtin echo hi	ksh --version	${.sh.version}	$KSH_VERSION	$ERRNO	set -o
ksh88	1	builtin: not found	bad option	bad substitution	not set	is set
ksh93	>1	builtin: hi: not found	bad option	Version M-12/28/93e	not set	not set
pdksh	0	hi	unknown option	bad substitution	@(#)PD KSH v5.2.14 99/07/13.2	not set	adds braceexpand, login, nohup, physical, posix, stdin, vi-esccomplete, vi-show8, vi-tabcomplete

if [ "$BASH" ]; then echo bash; elif [ "$ERRNO" ]; then echo ksh88; elif [ "$(builtin)" ]; then echo ksh93; else echo pdksh; fi