Question

!C:\Perl\bin\perl.exe

use strict;
use warnings;


my $numArgs = $#ARGV + 1;
print "thanks, you gave me $numArgs command-line arguments.\n";



while (my $line = <DATA> ) { 
    foreach my $argnum (0 .. $#ARGV) {
        if ($line =~ /$ARGV[$argnum]/)
            {
                print $line;
            }
    }
} 

__DATA__ 
A
B
Hello World :-)
Hello World !

when I passed one arg, it works well.
Such as I run test.pl A or test.pl B or **test.pl Hello”

when I passed two args, it works some time only.

Successful: When I run test.pl A B or test.pl A Hello or **test.pl B Hello”

Failed: when I run test.pl Hello World*

Produced and output duplicate lines:

D:\learning\perl>t.pl Hello World
thanks, you gave me 2 command-line arguments.
Hello World :-)
Hello World :-)
Hello World !
Hello World !

D:\learning\perl>

How to fix it? Thank you for reading and replies.

[update]
I don’t want to print duplicate lines.

Answer 1

I don’t see the problem, your script processes the __DATA__ and tests all input words against it: since “Hello” and “World” match twice each, it prints 4 rows.

If you don’t want it to write multiple lines, just add last; after the print statement.