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Help with tail command

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# 1  
Old 02-04-2010
Java Help with tail command
Hi All,

My query seems to be silly but Iam unable to find where the exact problem lies.

I have a script to unzip set of files

here is the script

Code:
#!/bin/ksh
Count=`cat /home/gaddamja/Tempfile | wc -l`
while [ $count -ge 1 ]
do
Filename=`cat /home/gaddamja/Tempfile |tail -$Count | head -1`
cd /home/gaddamja/FilesDirectory
`gunzip $Filename`
echo " $Filename unzipped successfully"
$Count=`expr $count - 1`
done
echo "Unzipping completed"


from second line I am getting the count but in 5th line when i use 'Count' with tail its not working

it says
Code:
tail: cannot open input

could you pl suggeest me the right way to use it.

quick reply much appriciated!

Many thanks in advance
Last edited by pludi; 02-05-2010 at 02:17 AM.. Reason: code tags, please...
# 2  
Old 02-05-2010
hmm.. whats in Tempfile?
# 3  
Old 02-05-2010
try This

Code:
Filename=`cat /home/gaddamja/Tempfile |tail -"$Count" | head -1`

# 4  
Old 02-05-2010
What is the output from these two commands:

Code:
file /home/gaddamja/Tempfile

sed -n l /home/gaddamja/Tempfile

As suggested above there is something funny about that file.
# 5  
Old 02-05-2010
There are some imperfections in your script, try this one:

Code:
#!/bin/ksh

count=$(wc -l < /home/gaddamja/Tempfile)

cd /home/gaddamja/FilesDirectory

while [ $count -ge 1 ]
do
  Filename=$(tail -$count /home/gaddamja/Tempfile | head -1)
  gunzip $Filename
  echo " $Filename unzipped successfully"
  count=$(($count - 1))
done
echo "Unzipping completed"

Last edited by Franklin52; 02-05-2010 at 12:35 PM..
# 6  
Old 02-05-2010
Interestingly franklin52 version should generate the same error because $Count is empty at the time of the "tail" command thereby causing "tail - ". Update: franklin52 version now has $count and therefore does not have the problem in that form.

What is weird is why $Count is empty (or has a leading space character) in the original script also causing "tail - ".
Hmm. In many old scripts I have a sed to remove a spurious space character from the output of "wc -l".
Last edited by methyl; 02-05-2010 at 12:47 PM..
# 7  
Old 02-05-2010
Quote:
Originally Posted by methyl
Interestingly franklin52 version should generate the same error because $Count is empty at the time of the "tail" command thereby causing "tail - ". Update: franklin52 version now has $count and therefore does not have the problem in that form.

What is weird is why $Count is empty (or has a leading space character) in the original script also causing "tail - ".
Hmm. In many old scripts I have a sed to remove a spurious space character from the output of "wc -l".
The problem is that he's using $count and $Count interchangeably.
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