A Typical Perl Script to Search Info in a File

This one is where I excerpted from the book “perl for dummies”.

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$TheDB = 'edata.txt';


open(INDB, $TheDB) or die "The database $TheDB could " . "not be found.\n";

while(1) {

  print "\nDo you want to search by employee ID (I), " . " or quit (Q): ";

  $DoSearch = <STDIN>;
  chomp($DoSearch);
  $DoSearch =~ tr/A-Z/a-z/;

  if($DoSearch eq 'q') { last }

  unless($DoSearch eq 'i') {
    print "You must enter either I or Q.\n";
    next;
  }

  print "Search for ID number: ";
  $SearchFor = <STDIN>;
  chomp($SearchFor);

  seek(INDB, 0, 0);   ##search from the beginning of file.

  $SuccessCount = 0;

  while(<INDB>) {
    $TheRec = $_;
    chomp($TheRec);
    ($LastName, $FirstName, $ID, $Tel) =
      split(/\t/, $TheRec);
    if($ID eq $SearchFor) {
      $SuccessCount = $SuccessCount + 1;
      print "$ID: $FirstName $LastName, ext. ". "$Tel\n";
    }
  }

  if($SuccessCount == 0) { print "No records found.\n" }
  else { print "$SuccessCount records found.\n" }
}

print "Program finished.\n";

We can learn the use of while, endless loop, file-handle, last, tr, seek, $_, eq, split, string concatenation if-else, chomp, ==, eq all these things in one perl script.