vighneshmufc:

You have an error in this line:

while (my ($row) = <$fh2>) {

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Since $row is in parenthesis, you're doing an assignment in list context. So all the lines in $fh2 are read, and the first one is passed into $row, and the rest are discarded.

Change the line to:

while (my $row = <$fh2>) {

[download]

and then it should work better for you.

Here's a little demonstration:

$ cat t.pl
use strict;
use warnings;

# Scalar context
my $row = <DATA>;
print $row;

# Array context
my ($a) = <DATA>;
print $a;

# Now there's nothing left!
my $c = <DATA>;
print $c;

__DATA__
Now is the time
for all good men
to come to the aid
of their party

$ perl t.pl
Now is the time
for all good men
Use of uninitialized value $c in print at t.pl line 14, <DATA> line 5.

[download]

Notice that we read the first line in scalar context, and then we print the first line successfully.

Next, we read a line in array context, and print the second line successfully.

Finally, we try to read the next line, but there's no data left! All of it was read earlier!

...roboticus

When your only tool is a hammer, all problems look like your thumb.

In reply to Re^8: Filtering Output from two files by roboticus
in thread Filtering Output from two files by vighneshmufc

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