Perl:How to insert line in a file? - regex

Question

I am reading from two files. I'm trying to insert a line from file2 to file1 whenever column 1 contents matches.
##FILE1
1 wr 5769 78670002 fqefq
3 wr 5769 78650003 hfhhg
5 wr 5769 88990001 dfdsv
##FILE2
1 Step1
3 Step3
5 Step5
Desired Output:
1 wr 5769 78670002 fqefq
Step1
3 wr 5769 78650003 hfhhg
Step3
5 wr 5769 88990001 dfdsv
Step5
Code tried:
my $rk="rk.log";
open(my $tt, "<$rk" ) or die "Could not open file $trk: $!";
while (<$tt>) {
if ($_ =~ /^(\d+)\s+wr\s+5769\s+(\w+)\s+\.*/gm) {
open(p1,"<$temp1") or die "Could not open file $temp1: $!";
while (my $newl = <p1>) {
my #fs1 = split " ", $newl;
if ($fs1[0] eq $1){
print "#fs1\n";
print "step $2\n";
} else {
print "#fs1\n";
}
}
}
}
close p1;
close $tt;
Above code doesn't giving the desired output. Can anyone suggest me better way to do it?
Update ##FILE2
2 Step1
4 Step3
6 Step5

Answer 1

Hopefully, a bit of pseudocode will be enough to get you on the right track.
Read file2 into a hash (where the key is the integer and the value is the whole line)
Open file1
Read file1 a line at a time
Print the line from file1
Extract the integer from the start of the line from line1
If that integer exists in your hash
Print the line from file2

Answer 2

I believe the simplest method would be to import the two files into separate strings, then create a loop which:
Finds match in file 1. (Include line breaks in your matches)
Appends match to third string.
Deletes match from file 1. (Replace with nothing)
Finds match from file 2. (Include line breaks in your matches)
Appends match to third string.
Deletes match from file 2.
This way you will sequentially order all of your matches from the two files into a string that you can export as a file.

Answer 3

This is works for me:
use Tie::File;
my $fle1 = $ARGV[0]; my $fle2 = $ARGV[1];
open(FL2, $fle2) || die "Couldn't read file $fle2\: $!\n";
my $flecnt2 = do { local $/; <FL2>; };
close(FL2);
my #array;
tie #array, 'Tie::File', $fle1 || die "Error: Couldn't read and write \"$fle1\" file: $!";
my $str = join "\n", #array;
$str=~s#^([^\s]+)\s(.+)$# my $fulcnt=$&;
if($flecnt2=~m/^$1\s+(.+)$/m)
{
$fulcnt .= "\n$&";
}
($fulcnt);
#egm;
#array = split/\n/, $str;
untie #array;