Shell Programming and Scripting

Hi,
some one please help me

I have two files.each having two coloumns and many rows
I want to write the difference between the two files to a new file

sample:


file1

1 2
4 5
8 6

file2

1 2
3 5
8 4
3 6
9 7


I tried with 'diff' and 'comm' commands.i got the output that include differenet rows in both the files as well as extra rows in second file.

I got the output as.

4 5
3 5
8 4
8 6
3 6
9 7

but I want the output like

4 5
3 5
8 4
8 6

I want only the changes in rows from first file to second file in the output.Not the extra rows in table 2.


Please guide me
regards
bab123

Use grep, check the manpage for the options -v and -f.

Regards

An inefficent way in shell script would be to read file1 record-by-record then look at the corresponding record in file2. This script is unsuitable for large files and would be better in awk where you could read a both files in parallel.
The script assumes that file1 does not contain more records than file2.

#!/bin/ksh
COUNTER=0
cat file1|while read LINE1
do
COUNTER=`expr $COUNTER + 1`
LINE2=`cat file2|head -${COUNTER}|tail -1`
if [ ! "${LINE1}" = "${LINE2}" ]
then
echo "${LINE1}"
echo "${LINE2}"
fi
done

Thanks methyl.
Can you help me using the awk command

Sorry, there are many better than I with awk on this forum.
Please post the number of records in the file so folks know whether efficency is important.

Thanks for the reply.
There are around 70,000 records in the file

Try this:

Code:

awk 'NR==FNR{a[$0];next}!($0 in a)' file1 file2

Regards