#! perl -slw
use strict;

my %charsByLine;
my %freqCharsPerLine;
my %chars;
while( <> ) {
	chomp;
	for( split '', $_ ) {
		$chars{ $_ } = 1;
		push @{ $charsByLine{ $_ } }, $.;
		$freqCharsPerLine{ $. }{ $_ }++ ;
	}
}
my $last = $.;

## Eliminate chars that do not appear in every line
@{ $charsByLine{ $_ } } != $last and delete $chars{ $_ } for keys %chars;

## Eliminate chars where they appear a different number of time per line
for my $char ( keys %chars ) {
	my $previousCount = $freqCharsPerLine{ 1 }{ $char };
	for my $line ( 2 .. $last ) {
		if( $freqCharsPerLine{ $line }{ $char } != $previousCount ) {
			delete $chars{ $char };
			last;
		}
	}
}

if( keys %chars == 1 ) {
	print "The delimiter for this file is: ", keys %chars;
}
elsif( keys %chars ) {
	print "Candidate delimiters for this file are: ", keys %chars;
}
else {
	print "Unable to determine a likely candidate for this file!";
}