Mostly what Graff was suggesting was that you should get your input from the command line parameters rather than prompt the user for them. That makes it easier to use the script in an automated context where you may wish to do several runs with different parameters perhaps. In essence it means replacing:

print "Enter the output file you would like to analyze: ";
chomp (my $filename = <STDIN>);
print "Enter the isotope you want to extract (ex: Am-241): ";
chomp (my $iso= <STDIN>);

[download]

with something like:

# Validate parameters
@ARGV == 2 or error ("Too few parameters");
$ARGV[0] =~ /[A-Z][a-z]?-\d{1,3}/ or error ("Expected an isotope first
+");
-f $ARGV[1] or error ("<$ARGV[1]> is not a file");

# Extract parameters
my ($iso, $filename) = @ARGV;

...

sub error {
    my $msg = shift;

    print <<"USAGE";
Error: $msg.

ExtractIso parses a given dibbly report file and extracts the
record for a given isotope. Use as:

    ExtractIso <iso> <filename>

<iso> is the isotope to be extracted. For example Am-214.

<filename> is the filename (with path as required) of the
record file.

For example:

    Extract Am-214 dibbly.dat

would extract and print the record for Am-214 from the 
dibbly.dat file in the current directory.
USAGE

    exit -1;
}

[download]

The error sub uses a HEREDOC to provide an error diagnostic and usage information.

DWIM is Perl's answer to Gödel

In reply to Re^3: REGEX on multiple lines by GrandFather
in thread REGEX on multiple lines by igotlongestname

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