Read 2 files alternatively based on condition.

Shell Programming and Scripting
1

Experts,

What would be the code in ksh/perl to read 2 files alternatively, based on the following condition.

while reading file 1 we check if a blank line is encountered,
if yes, then we read file 2 unless a blank line is encountered in file 2
if we have a blank line in file 2 we come back to file 1 and continue reading file 1 unless a blank line is encountered, and then continue to file 2, till reading both the files have complete.

Thanks in advance,
:confused:

2

Solution already provided there

The script give the output to console. if you want to save the output as a file, use the write file handler at end of the program or redirect the output to a file.

cmd#   perl scriptname.pl > your_output_file_name

   or

open (FOUT, ">output.txt") || die "Cannot create the output file";
for (my $i = 0; $i<=$#file1; $i++) {
print FOUT "\n----- Group ", $i+1," ------\n", "$file1[$i]\n", "$file2[$i]\n";
}
close (FOUT);
3

Thanks for you reply,
But the code you provided doesn't work...
it doesn't print anything.

4

I just show the piece of code how to write the output to a file. I expect you collate code in the existing example. OK, tried the below code.

#!/usr/bin/perl
use strict;
use warnings;
my $file1=open_file("file1.txt");
my $file2=open_file("file2.txt");
my @file1 = split(/\n{2,}/, $file1);
my @file2 = split(/\n{2,}/, $file2);
open (FOUT, ">output.txt") || die "Cannot create the output file";
for (my $i = 0; $i<=$#file1; $i++) {
print FOUT "\n----- Group ", $i+1," ------\n", "$file1[$i]\n", "$file2[$i]\n";
}
close (FOUT);
sub open_file
{
 my ($fname)=@_;
 undef $/;
 open (FIN, "<", "$fname") || die "Cannot open the input file $fname : $!";
 my $fcontent=<FIN>;
 close (FIN);
 return "$fcontent\n";
}