I need a better way to loop in the shell...

[Robert Eckardt]

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.
> 
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--
Dr. Robert Eckardt    ---    Robert.Eckardt at Robert-Eckardt.de