Reading a File in Perl

Two approaches are shown here. Reading the whole file and reading it line by line.

The whole file

sub ReadFile {
       my ($filename) = @_;
       
       open TMP,$filename or die "Couldn't open '$filename': $!";
       local $/ = undef; # eat the whole file
       my $text = ;
       close TMP;
       return $text;
}

Line by line

my $textfile = "blah.txt";

open TEXTFILE, $textfile or die("Could not open text file '" . $textfile . "': $!");
foreach $line (<TEXTFILE>) {
    chomp($line);              # remove the newline from $line.
    # do line-by-line processing.
    if($line =~ [insert some regexp here]) {
      # you can now access the results of your regexp using $1,$2,...
    }
}