Date: Wed, 14 Dec 2005 06:00:15 +0100 From: "Robert Eckardt" <rol@robert-eckardt.de> To: user <user@dhp.com>, freebsd-questions@freebsd.org Cc: owner-freebsd-questions@freebsd.org Subject: Re: I need a better way to loop in the shell... Message-ID: <20051214045249.M61301@Robert-Eckardt.de> In-Reply-To: <Pine.LNX.4.21.0512132340550.8684-100000@shell.dhp.com> References: <Pine.LNX.4.21.0512132340550.8684-100000@shell.dhp.com>
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On Tue, 13 Dec 2005 23:44:42 -0500 (EST), user wrote > I always do loops in /bin/sh like this: > > for f in `cat file` ; do rm -rf $f ; done Hi, try instead: cat file | while read f ; do rm -f "$f" ; done In your command `file' is presented as 10,000 Maniacs MTV Unplugged - 01 - These Are Days.mp3 10,000 Maniacs MTV Unplugged - 02 - Eat For Two.mp3 10,000 Maniacs MTV Unplugged - 03 - Candy Everybody Wants.mp3 ... while the for-loop cuts the arguments at spaces. read reads the rest of the line in its last (and only -- in this case) argument into a single variable. Regards, Robert > > Easy. I like doing it like this. > > The problem is, when I am dealing with an input list that has > multiple words per line, this chops it up and treats every word as a > new line... > > For instance, lets say I have a file full of filenames, like this: > > # cat file > > 10,000 Maniacs MTV Unplugged - 01 - These Are Days.mp3 > 10,000 Maniacs MTV Unplugged - 02 - Eat For Two.mp3 > 10,000 Maniacs MTV Unplugged - 03 - Candy Everybody Wants.mp3 > > and I try to use the above loop on it, it thinks that every word is > a line ... the above loop will attempt to delete the following files: > > 10,000 > Maniacs > MTV > Unplugged > - > 01 > - > These > > (and so on) > > Even if I quote the variable $f, like: > > for f in `cat file` ; do rm -rf "$f" ; done > > it still does the same thing. > > ----- > > So my question is, what is a nice simple way to loop in the shell, as > close to what I am doing above as possible, that does not have this > problem ? Should I just be using something other than `cat` ? Or > what ? > > THanks. > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org" -- Dr. Robert Eckardt --- Robert.Eckardt@Robert-Eckardt.de
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