This is my problem: I have a tab delimited file (file_A.txt) like this 
a1    b1    c1    d1
a2    b2    c2    d2
a3    b3    c3    d3
a4    b4    c4    d4

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starting form the top of the file I need 1. to get the the value in the 3rd column (c1)

2. search in a second file (file_B.txt, not tab delimited and quite messy) all the matches for it.

3. when a match is found, I would like to append to the current value (c1), the value of 4th column (d1) in file_A.txt, separated by a space.

4. go back to the first file (file_A.txt), get the the value in the 3rd column in the second row (c2) and do another round of search and insert the value of d2 in the second file (file_B.txt).

5. go ahead with the search and replace until the end of file_A.txt is reached. I am an absolute newbee and I put together this code that does not work very well. 

#!/usr/bin/perl
open (datafile, "file_A.txt");
@fileinput = split("\t", <datafile>);
    
for ($i = 2; $i <=200;){
    open(OF, "file_B.txt"); #file_B.txt contains the original file 
    open(NF, ">file_B_out.txt"); #file_B_out.txt contains the processe
+d output
    while ($line = <OF>) {
    print "$fileinput[$i]\n";
    print "$i\n";
    $line =~ s/$fileinput[$i]/$fileinput[$i+1]/g;
    #print $line;
    print NF $line;
    
    }
$i=$i+4;
}
close(NF);
close(OF);

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1. I don`t know how to tell perl to loop until the end of file_A.txt, so I have just used a for statement

2. the search and replace routine does not work and I don`t understand why

Any suggestions and possibly example would be really appreciated

thanks.

In reply to Get data from a file to search and replace within a second file by biscardi

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