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From: walter@mecky.UUCP (Walter Mecky)
Newsgroups: comp.unix.shell
Subject: Re: trap 0 in /bin/sh
Message-ID: <893@mecky.UUCP>
Date: 29 Mar 91 01:02:38 GMT
References: <1991Mar27.153352.4421@robobar.co.uk>
Reply-To: walter@mecky.UUCP (Walter Mecky)
Organization: MIKROS Systemware, Buettelborn/W-Germany
Lines: 15

In article <1991Mar27.153352.4421@robobar.co.uk> ronald@robobar.co.uk (Ronald S H Khoo) writes:
< Can someone explain why these two commands give different output ?
< Is there some subtlety about the "trap" command that I don't understand ?
< 
< 	$ ( trap 'echo foo' 0 ; true )
< 	$ ( trap 'echo foo' 0 ; : )
< 	foo

Looks like a bug in sh, ksh executes echo with both commands.
I suppose, the subshell for the commands in ( ... ) looks to 
the last command bevor ) and, if it's not a builtin, does only exec(2),
instead of the usual fork(2)/exec(2). So sh cannot execute the trap
commands.
-- 
Walter Mecky	[ walter@mecky.uucp	or  ...uunet!unido!mecky!walter ]