# Write to text file:
open(my $fh, ">", $filename)
    or die "Failed open for write! $!";
print $fh "Foo\n";             # Prints to file
close $fh;                     # Close file

# Read from text file:
open($fh, "<", $file_to_read) or die "Couldn't open! $!";
my $line = <$fh>;              # Reads a line.
chomp $line;                   # Removes eol chars (CR,LF)
close $fh;