8.22.1. Problem

8.22.2. Solution

use File::Compare;

if (compare($FILENAME_1, $FILENAME_2) =  = 0) {
  # they're equal
}

if (compare(*FH1, *FH2) =  = 0) {
  # they're equal
}

if (compare($fh1, $fh2) =  = 0) {
  # they're equal
}

8.22.3. Discussion

# ensure all filehandles in @fh hold the same data
foreach $fh (@fh[1..$#fh]) {
  if (compare($fh[0], $fh)) {
    # $fh differs
  }
}

use Text::Diff;

$diff = diff(*FH1, *FH2);
$diff = diff($FILENAME_1, $FILENAME_2, { STYLE => "Context" });

In addition to filehandles, diff can also take filenames, strings, and even arrays of records. Pass a hash of options as the third argument. The STYLE option controls the type of output returned; it can be "Unified" (the default), "Context", or "OldStyle". You can even write your own class for custom diff formats.

The value returned by diff is a string similar to the output of the diff(1) program. This string is in valid diff format, suitable for feeding into patch(1). Although Text::Diff will not always produce the same output as GNU diff, byte for byte, its diffs are nevertheless correct.