Linux programming help

Former Member

I need to write a program to do something like a 'vlookup' in excel. I want to match data from file2 based on two fields (where both match) in file1, and for matching lines, add the data from two of the fields from file2 to file1.

If anyone knows something in perl or awk that can do this, I'd be very happy

e.g.:
(match on field 1 and 2, and append column 4 and 5 to column 5 and 6)

file1
1 A X a
2 B Y b
3 C Z c
4 D X d
5 E Y e

file2
1 A Y b
2 C Z c
3 D X d
4 E Y e
5 E Z c

output
1 A X a Y b
2 B Y b
3 C Z c
4 D X d
5 E Y e Z c

Former Member

http://www.linuxquestions.org/questions/programming-9/

Former Member

This is more of a DB task really, but I guess it depends where your files are coming from

Tell me more about your data.

Will the first field always match 1:1 between the two files? If not is the the combination of the first two fields unique in both files?

Are the files in the same order as each other?

anyway, a simple script to produce the required results from the provided test data:

#!/bin/sh

if [ $# = 1 -a X$2 = X-h ]
then
  echo usage: $0 file1 file2
  exit 0
fi

if [ $# != 2 ]
then
  echo usage: $0 file1 file2
  exit 1
fi

[ -r $1 ] && exec 3< $1 || (echo can\'t read \"$1\"; false) || exit 3
[ -r $2 ] && exec 4< $2 || (echo can\'t read \"$2\"; false) || exit 3


while read -u3 first second rest
do
  read -u4 first2 second2 rest2
  if [ X"$first" = X"$first2" -a X"$second" = X"$second2" ]
  then
    echo $first $second $rest $rest2
  else
    echo $first $second $rest
  fi
done

Former Member

So, was that what you needed, or do you need a more general version?

Former Member

Hi guys

Really sorry I didn't reply, I completely forgot about this thread! I got the job done using a version of your code, thanks a lot BG.