[Chester LUG] Help with a bash script

[David Holden]

On 18/10/10 21:49, Stuart Burns wrote:
> Dave, you must be a bash Jedi!
> 
> It does work, and I can kind of trace how it works, but would you mind
> explaining it a bit more ?
> Cheers muchly. I owe you a beer, if your at the LUG next week ?

You still owe me a meal matey ;)

IFS=' ' this set the fields seperator for the "read".

basically it then loops over the rows, gets the first column (based on
the IFS) echo's it without newline, then for each of these "col1"s cats
the whole file again and picks out col2 (using awk) that have matching
"col1"s, then collapses them to one line using tr '\n' ' ', the final
echo does the newline. This all has to then be sorted and uniq'ed to
remove repetition.

 Cheers,

  Dave.




> 
> Cheers muchly. I owe you a beer, if your at the LUG next week ?
> 
> 
> On 18 October 2010 21:26, David Holden <dh at iucr.org
> <mailto:dh at iucr.org>> wrote:
> 
>     Hi Stuart,
> 
>      VERY quick hack but it may work, the grep allows # comments
> 
> 
>     IFS=' ';
> 
>     datfile="1.dat"
> 
>     (
>     cat $datfile | sort | grep -v \# | while read data
>     do
>      data_array=(`echo "$data"`)
>      col1=${data_array[0]}
>      echo -n "$col1 "
>      cat $datfile  | sort  | grep "$col1" | awk '{print $2}' | tr '\n' ' '
>      echo ""
>     done
>     ) | sort | uniq
> 
> 
>     Dave.
> 
> 
>     On 18/10/10 17:44, Stuart Burns wrote:
>     > Hi everyone,
>     >
>     > I am hoping someone can help me a bit here. I am creating a cript that
>     > deals with volume groups. However my bash skills fall short.
>     >
>     > I have a file that looks like this
>     >
>     > Vg955-01 /dev/diska1
>     > Vg955-01 /dev/diska2
>     > Vg978-01 /dev/disk45
>     > Vg978-04 /dev/disk13
>     >
>     > You get the picture.
>     >
>     > Now what I am trying to do is get all the vg parts followed by the
>     > constituent disks. Ie above should look like:
>     >
>     > Vg955-01 /dev/disk1a /dev/diska2
>     > Vg978-01 /dev/disk45
>     > Vg978-04 /dev/disk13
>     >
>     > I cant really think of an easy way to do it without resorting to perl.
>     > Can anyone help?
>     >
>     > Regards
>     >
>     > Stu
>     >
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>     >
> 
>     --
>     Dr David Holden. (dh at iucr.org <mailto:dh at iucr.org>)
> 
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> 
> 
> 
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-- 
Dr David Holden. (dh at iucr.org)