Date: Wed, 16 Jan 2002 01:18:21 +0800 (CST) From: =?iso-8859-1?q?adrian=20kok?= <adriankok2000@yahoo.com.hk> To: Giorgos Keramidas <keramida@freebsd.org> Cc: questions@freebsd.org Subject: Re: /dev/null 2>&1 Message-ID: <20020115171821.89227.qmail@web21208.mail.yahoo.com> In-Reply-To: <20020114211029.GD31045@hades.hell.gr>
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Dear Thank you very much for your reply I also have question about it What is the advantage and the different /dev/null 2>&1 Sometimes I only use this one make buildworld >buildworld.log not make buildworld >buildworld.log 2>&1 & Thank you again --- Giorgos Keramidas <keramida@freebsd.org> wrote: > On 2002-01-15 01:33:04, adrian kok wrote: > > Dear all > > > > What is the meaning of /dev/null 2>&1 > > > > Thank you > > You'll see constructs like this in scripts that > read: > > command >/dev/null 2>&1 > > That is a Bourne shell idiom (does not work in CSH > and friends), that > means ``redirect standard output to /dev/null'' and > then ``redirect > file-descriptor 2 (stderr) to the same place as 1 > (stdout)''. > > The purpose of all this is to stop `command' from > producing *any* kind > of output, on standard output and error. > > Another use could be to save all output from a > command in a file, both > standard output and standard error. I customarily > build my kernels > and update my FreeBSD systems with commands like > this: > > # cd /usr/src > # make buildworld >buildworld.log 2>&1 & > # logout > > Then after buildworld finishes ... > > # cd /usr/src > # make buildkernel >buildkernel.log 2>&1 & > # logout > > This way, all output from `make buildworld' is saved > in the file > /usr/src/buildworld.log and all output from `make > buildkernel' is > saved in /usr/src/buildkernel.log. A few hours > later, I can browse > the file for interesting messages. > > Cheers, > > -- > Giorgos Keramidas . . . . . . . . . > keramida@{ceid.upatras.gr,freebsd.org} > FreeBSD Documentation Project . . . > http://www.freebsd.org/docproj/ > FreeBSD: The power to serve . . . . > http://www.freebsd.org/ > > ATTACHMENT part 2 application/pgp-signature _______________________________________________________________________ Do You Yahoo!? Get your free @yahoo.com.hk address at http://mail.english.yahoo.com.hk To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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