Hi there,

I have two very long files like:

file1: two fields

Code:

1 123 
1 125
1 234
2 123
2 234
2 300
2 312
3 10
3 215
4 56
...

file2: 6 fields

Code:

1 123 0 1 0 0
1 126 2 1 0 0
2 123 0 1 0 1
2 138 1 1 1 1
2 300 0 1 2 3
2 311 2 4 6 0
3 120 3 4 1 0
3 215 1 1 2 1
3 216 0 2 1 5
3 345 8 0 1 0
3 357 0 1 1 1
3 500 2 1 0 1
4 17  6 1 0 2
4 70  0 1 0 1
...

The numbers of lines in file1 and file2 are not equal.

I want to get an output file like

file3: 6 fields, and the first two fields are exactly the same as the first two fields in file1. For example, the line with the first two field "1 123" has a match in file2: "1 123 0 1 0 0", then print the whole line in file2:"1 123 0 1 0 0" to file3. If one line in file1 does not have a match in file2, e.g. "1 125", then print "1 125 0 0 0 0" to file3.

Code:

1 123 0 1 0 0
1 125 0 0 0 0 
1 234 0 0 0 0
2 123 0 1 0 1
2 234 0 0 0 0
2 300 0 1 2 3
2 312 0 0 0 0
3 10  0 0 0 0
3 215 1 1 2 1
4 56  0 0 0 0
...

I am wondering if this can be done using awk or join or any other in linux? Since the files are very large, I really want it to be fast. Thanks a lot~~~

Note: Field 2 in both file1 and file2 has only number values, but field 1 in both files may have characters too. The two fields are sorted. And in both files, this kind of situation will not happen, no duplicates.

Code:

1 123
1 123
...

Also we do not need to consider the lines in file2 which do not have any match in file1, for example "1 126 2 1 0 0" (no match in file1), then this line should not be added to file3.