UNIX for Dummies Questions & Answers

Hi can anyone show me how to search through a file (multiple columns) and based on say one column if empty and another being popluted and if both senario's are true then get information from another file matching the data from the populated column based upon the populated column and bring through details adjacent to this column....sort of like a vlookup in MS Excel only I'd need to sort first on the blanks, then the populated column, then do a vlookup...which ofcourse works but I need to be able to do this with muy server--- DG-Unix

many thanks in advance

Take a simple example. Say you have two files...

Code:

==> file1 <==
key1,value1
key2,value2
key3,
key4,value4
key5,value5

==> file2 <==
key1,value1b
key2,value2b
key3,value3b
key4,value4b
key5,value5b

You can use awk to lookup the missing values...

Code:

awk '
  BEGIN {
      OFS = FS = ","
      while (getline < "file2" > 0)
          a[$1] = $2
  }
  {  
      if ($1 && !$2)
          $2 = a[$1]
      print
  }
  ' file1 > file3

The resulting file looks like this...

Code:

==> file3 <==
key1,value1
key2,value2
key3,value3b
key4,value4
key5,value5

Thanks for that ...But is there no way of doing a lookup ...meaning if $string found then hunt through another file and retrieve the matching adjacant line