CODEWITHSUNDEEP
linuxawk
Tesse M
Tesse M

Reputation: 111

Comparing two files field by field in Linux

I am trying to compare two files (separted by comma and space) using 3 fields (field 1,2, 5 from file1 and 1,2,5 from file2) if the two files match i want the whole record of file2 concatenated with the last filed of file1 using awk. for example file1:

1, 4, abebe, kebede, 25, 101, 42
1, 4, abebe, debebe, 42, 201, 47
1, 4, abebech, kebede, 17, 33, 57

file2:

1, 4, abebe, kebede, 25, 101, 42
1, 4, Tesse, debo, 25, 101, 42
1, 4, derartu, tulu, 25, 101, 42

output:

42, 1, 4, abebe, kebede, 25, 101, 42
47, 1, 4, Tesse, debo, 25, 101, 42
57, 1, 4, derartu, tulu, 25, 101, 42

I am new for linux.... any help is apprciated

Upvotes: 0

Views: 1598

Answers (2)

Dennis Williamson
Dennis Williamson

Reputation: 359935

Since fields 1, 2 and 5 of record 1 in file 1 match all the records in file 2 I have listed the files as arguments in the opposite order in order to get the output you want.

awk 'BEGIN {OFS = ", "} NR == FNR {a[$1, $2, $5] = $NF; next} $1 SUBSEP $2 SUBSEP $5 in a {print a[$1, $2, $5], $0}' file2 file1

The NR == FNR block forms a loop that reads the file which appears first in the argument list into an array. When the record number (NR) and the file record number (FNR) are no longer equal, processing continues to the file which is named as the second argument.

There, the array is checked to see if the fields from the two files match. If so, the corresponding saved field and the current record are output.

Upvotes: 1

William Pursell
William Pursell

Reputation: 212208

My first reading of the problem lends itself to this solution:

awk '{getline t < "file2"; split( t, a );
    if( a[1]a[2]a[5] == $1$2$5) print $NF",", t}' file1

But it appears that the question is actually: 'Given file1 in which we know that any record in which fields 1, 2, and 4 are the same the final field is also the same, find all lines in file2 with corresponding fields 1, 2, and 4 and output that line with the final field from file1 prepended. In which case the solution given by Dennis works.

Upvotes: 1

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