Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!julius.cs.uiuc.edu!psuvax1!rutgers!cbmvax!jesup
From: jesup@cbmvax.commodore.com (Randell Jesup)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Unix like 'tail -f'
Message-ID: <17704@cbmvax.commodore.com>
Date: 17 Jan 91 06:57:25 GMT
References: <1991Jan17.034047.18447@eecs.wsu.edu>
Reply-To: jesup@cbmvax.commodore.com (Randell Jesup)
Organization: Commodore, West Chester, PA
Lines: 23

In article <1991Jan17.034047.18447@eecs.wsu.edu> rnelson@yoda.UUCP (Roger Nelson - Grad Student) writes:
>------
>
>Am I correct in my observation that Amiga DOS does not allow you to access
>a file in any way until it is fully closed? 
>
>Does there exist a UNIX like tail utility?  
>Could similar functionality be achieved using something like Matt Dillon's
>fifodev (which I intend to look at)?

	If it was opened MODE_OLDFILE, you can read it while it's being
extended.  If it was opened MODE_NEWFILE (which truncates it), an exclusive
lock on the file is obtained, and no one else can open the file until it's
closed.  Many standard programs use MODE_NEWFILE, since it creates the file
if it doesn't exist.  In 2.0, MODE_UPDATE will open a file, creating it
if it doesn't exist, and only gets a shared lock.

-- 
Randell Jesup, Keeper of AmigaDos, Commodore Engineering.
{uunet|rutgers}!cbmvax!jesup, jesup@cbmvax.commodore.com  BIX: rjesup  
The compiler runs
Like a swift-flowing river
I wait in silence.  (From "The Zen of Programming")  ;-)