How about command line parameter checking? 
...
my $filename = $ARGV[0];
my ($name, $number);

die "Usage: $0 filename\n" unless $filename; # checking command line p
+arameter
...

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In reply to Re^2: How to extract Name and No from .vcf file. by pme
in thread How to extract Name and No from .vcf file. by shankonit

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