Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!samsung!munnari.oz.au!manuel!cmf851
From: cmf851@anu.oz.au (Albert Langer)
Newsgroups: comp.unix.sysv386
Subject: Re: cu/ecu through TCP/IP (plus ecu porting status)
Message-ID: <1991May21.132134.4781@newshost.anu.edu.au>
Date: 21 May 91 13:21:34 GMT
References: <1991May16.154418.24131@chinet.chi.il.us> <1061@aega84.UUCP> <1991May17.171141.27309@chinet.chi.il.us>
Sender: news@newshost.anu.edu.au
Organization: Computer Services Centre, Australian National University, Canberra, Australia.
Lines: 20

In article <1991May17.171141.27309@chinet.chi.il.us> les@chinet.chi.il.us 
(Leslie Mikesell) writes:

>I'm pretty sure it isn't possible to do locks right in a shell script.
>Creating a tmp file and using /etc/link to attempt to rename it to
>the agreed-upon lockfile name is OK if it works, but you can never
>safely test or remove an existing file.   Some version of ln might
>do what you want, but SysVr3 removes the target before attempting the
>new link. 

I was under the impression it is safe to use mkdir since unlike
linking a file, that is atomic. Anyone disagree?

e.g.:

[ mkdir $lockdir ] || echo "Already locked"

--
Opinions disclaimed (Authoritative answer from opinion server)
Header reply address wrong. Use cmf851@csc2.anu.edu.au