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Article View: gnu.bash.bug
Article #1079

Re: putting multiple cmds in bg using &

#1079
From: News system owner ID
Date: Thu, 21 Dec 1989 17:21
44 lines
2370 bytes
pwolfe@kailand.kai.com (Patrick Wolfe) writes:
< I've found something that acts different in Bash than in Csh (the shell I
< previously used).  To place a multiple command list in the background, it is
< neccessary to use parens to enclose the command.  For example:
< 
< 	date ; make ; date &
< 
< with Bourne Shell or Bash 1.04, runs the first two commands in the foreground
< and the last in the background, where C shell will create a background job
< which runs all three commands.

I'll have to re-read the csh man page, but at a glance I *swear* this
is a csh misfeature (aka. deliberate bug).  The csh man page is vague.
From csh(1):

     Pipelines can be separated by semicolons (;), in which  case
     they are executed sequentially. Pipelines that are separated
     by && or || form conditional sequences in which  the  execu-
     tion  of  pipelines on the right depends upon the success or
     failure, respectively, of the pipeline on the left.

[The way I read the above, "foo && bar" is a (conditional) sequence,
but "foo; bar" may or may not be an unconditional sequence.]

     A pipeline or sequence can be enclosed within parentheses `(
     )'  to  form  a  simple command that can be a component in a
     pipeline or sequence.

     A sequence of pipelines can be executed  asynchronously,  or
     in  the  background by appending an `&'; rather than waiting
     for the sequence to finish  before  issuing  a  prompt,  the
     shell  displays  the job number (see Job Control, below) and
     associated process IDs, and prompts immediately.


Anyway, in every other shell I've ever heard of ; and & are at the
same precedence level.  It's easier to remember, and more intuitive.
Please let's keep bash the way it is, and force people to do

	 (foo; bar) &

like they should have been doing in the first place.

		-- Paul Placeway
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!samsung!think!bbn!news
From: news@bbn.COM (News system owner ID)
Newsgroups: gnu.bash.bug
Subject: Re: putting multiple cmds in bg using &
Message-ID: <50009@bbn.COM>
Date: 21 Dec 89 17:21:31 GMT
References: <8912121932.AA20899@kailand.kai.com>
Reply-To: pplacewa@antares.bbn.com (Paul W Placeway)
Distribution: gnu
Organization: Bolt Beranek and Newman Inc., Cambridge MA
Lines: 44