Now, Read the Data Back

• When the visitor returns, he is prompted for his bearcat ID.
• You can read this into another Perl script, let's call it readdata.pl.
• readdata.pl opens the data file we wrote earlier.
• It reads each line into an array.
• It then converts each array element into three string elements, by parsing the array with the tilde character.
• It compares the first element to the entered bearcat ID.
• If the bearcat ID matches, it then remembers the other two fields for later use (writing to HTML or something of that nature).
• Step by step:

# Normal stuff to start out the script.

#!/usr/local/bin/perl
 
#    Use the CGI.pm library
use CGI;
 
# Make a new CGI object.
$query = new CGI;
 
#   Write out the content-type header followed by a blank line.
print $query->header;

#   Write the HEAD section, including the title.
print $query->start_html("Your Data");

# Get the data from the form.

$bearcatID = $query->param('bearcatID');

# Open accountdata.txt, the file that holds the data.
# Read the contents into the array @data,
# Then close the file.

open(PAGE, "<../accountdata.txt");
@data = <PAGE>;
close(PAGE);

# Loop through the @data array.  The loop will assign each element to the
# scalar $words.

foreach $words(@data) {

   # This is a little tricky.
   # The first three scalars, in the parenthesis, will hold the values that we parse
   # out of the $words element.
   # The $words element holds one line of data from the text file.
   # The =~ and / / says to split up $words, based on the parameters we have given it.
   # These parameters are: multiple non-whitespace characters (\S*) , the tilde \~
   # then more characters, another tilde, and more characters.
   # Note that we had to escape out the tilde with a \ because the tilde is a special
   # character.

   # For more information, see chapter 11 in the book.

  ($ID, $firstName, $lastName) = $words =~ /(\S*)\~(\S*)\~(\S*)/;

# Uncomment the following statements for debugging,
#  if you want to see what you are getting.
# print $ID;
# print $firstName;
# print $lastName;
 

# Assign the input data to a hash, for use later.
# Note that we are using the scalars that we retrieved from the file.

 $first{$ID} = $firstName;
 $last{$ID} = $lastName;

}

# Use the has and the bearcat ID to print a welcome message,
# using the hashes we defined above.

print "Welcome $first{$bearcatID} $last{$bearcatID} !";

#   End the form.
print $query->end_html;
 
 

 Other Handy Commands
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