Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!rutgers!mcdchg!laidbak!daveb
From: daveb@i88.isc.com (Dave Burton)
Newsgroups: comp.unix.questions
Subject: ksh != sh on traps
Keywords: ksh, sh, trap, exit, compatible
Message-ID: <1990Feb15.204949.14177@i88.isc.com>
Date: 15 Feb 90 20:49:49 GMT
Sender: daveb@laidbak.i88.isc.com
Organization: Interactive Systems nee Lachman Associates
Lines: 44

The 88b version of ksh was changed in a way that, to my eyes, is broken.
Below, ksh = 11/16/88b, oksh = 06/03/86, and sh = SunOS 3.5 /bin/sh.

Script started on Thu Feb 15 14:18:59 1990
-------------------1$ cat x
:
trap "echo doing trap 0" 0
trap "echo doing trap 1" 1

die() {
        trap
        echo "function: die()"
        exit 1
}

echo "main body"
die
echo "end of main"
exit 2
-------------------2$ sh x
main body
0: echo doing trap 0
1: echo doing trap 1
function: die()
doing trap 0
-------------------3$ oksh x
main body
0:echo doing trap 0
1:echo doing trap 1
function: die()
doing trap 0
-------------------4$ ksh x
main body
function: die()
-------------------5$ ^D
script done on Thu Feb 15 14:19:23 1990

The KornShell book is self-contradictory on this point: cf ppg 150-151 & 204,
and I cannot find any good reason to fathom such a change. Perhaps someone
else has an answer (beyond "ksh is broken")? What about workarounds that are
compatible with both sh and ksh?
--
Dave Burton
uunet!ism780c!laidbak!daveb