Using the -0 Option

The -0 option will let you change the record separator. This is useful if your records are separated by something other than a newline. Let's use the example of input records separated by a dash instead of a newline. First, you need to find out the octal value of the dash character. The easy way to do this is to covert from the decimal value, which will be displayed if you run the following command line.

perl -e "print ord('-');"

This program will display 45. Converting 45₁₀ into octal results in 55₈.

Next, you'll need an input file to practice with the following data held in a test file:

Veterinarian-Orthopedist-Dentist-

A program that reads the above data file using the diamond operators is now developed:

• The program will use the dash character as an end-of-line indicator.
• We set the record separator to be a dash using the #! switch setting method.
• Open a file for input.
• Read all of the records into the @lines array.
• One element in @lines will be one record.
• Close the file.
• Iterate over the @lines array and print each element.

The Perl code is:

#!perl -0055

open(FILE, "<test.dat");

@lines = <FILE>;

close(FILE);

foreach (@lines) {

    print("$_\n");
}

Hint Instead of using the command-line option, you could also say $/ = "-";. Using the command line is a better option if the line ending changes from input file to input file.

This program will display:

Veterinarian-
Orthopedist-
Dentist-

Notice that the end-of-line indicator is left as part of the record. This behavior also happens when the newline is used as the end-of-line indicator. You can use chop() or chomp() to remove the dash, if needed.