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Re: rpm check script problem



On Monday, Oct 9th 2006 at 11:58 -0400, quoth Tony Nelson:

=>At 11:46 PM +0800 10/9/06, ???? wrote:
=>
=>>2006/10/9, Dan Track <dan track gmail com>:
=>>> Hi
=>>>
=>>> I've got a script that should check which rpms are installed on the
=>>> system. Part of the script involves using file descriptors. I'm having
=>>> trouble understanding these file descriptors and was hoping someone
=>>> can clarify my mistake. As a simple script I wrote the following:
=>>>
=>>> #!/bin/bash
=>>> $filename=$1
=>>> $filename1=$2
=>>>
=>>> exec 9<&0 < $filename
=>
=>>The line in the script "exec 9<&0 <$filename" means "first copy fd0 to
=>>fd9, then redirect file to fd0", so in the following lines of the
=>>script fd9 is always the stdin.
=>
=>According to the Wikipedia link
=>
=>    exec 9<$filename
=>
=>seems more likely.

We still don't know what the goal is. All we have is a something that the 
author thought should do what he wants but doesn't work.

Look, exec 9< $filename will redirect $filename to stdin for the duration 
of the process. exec < $filename 9<&0 will do the same thing but will save 
the value of descriptor zero for the purpose of restoration. It's all a 
question of what you want to do.

-- 
Time flies like the wind. Fruit flies like a banana. Stranger things have  .0.
happened but none stranger than this. Does your driver's license say Organ ..0
Donor?Black holes are where God divided by zero. Listen to me! We are all- 000
individuals! What if this weren't a hypothetical question?
steveo at syslang.net


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