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Insert a line in a file by deleting that line from another file

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Top Forums Shell Programming and Scripting Insert a line in a file by deleting that line from another file
# 1  
Old 11-15-2012
IBM Insert a line in a file by deleting that line from another file
Hi all,

I have a huge file(size more that 5GB).
I want to do some manupulation with the records and write to another file.
As the size of the file is huge and there is a space constraint in that directory, I want to delete that record from first file after writing it in to second file.
Example:-
Code:
cat first.dat | while read line
do
echo $line| .........    >> second.dat
# Here after writing to second file i want to delete the same record from first.dat
done

can anyone please help me on this???

thanks in adv....
Last edited by Scott; 11-15-2012 at 04:58 PM.. Reason: Code tags, again
# 2  
Old 11-15-2012
You can use sed to match that line and delete it from first.dat:-
Code:
sed -i "/$line/,1d" first.dat

But the line pattern has to be unique or you will end up deleting similar matching lines.

---------- Post updated at 15:23 ---------- Previous update was at 15:19 ----------

Another option is to use a COUNTER variable which you can increment for each line read and use the COUNTER variable to delete that particular line.
Code:
COUNTER=1
cat first.dat | while read line
do
   echo $line| .........    >> second.dat
   sed -i "${COUNTER}d" first.dat
   COUNTER=$( expr $COUNTER + 1 )
done

# 3  
Old 11-15-2012
As i am working in AIX, there is no "-i" option in sed
# 4  
Old 11-16-2012
first of all, reading the 5GB file using cat and while is not advisiable.

you need to choose awk,perl or pyton to process the file. in what conidtion, you want to remove the lines from the source file ?

give some input data and expected output.
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