#!/usr/local/bin/perl
my $ligne;
my $corpus = "file.txt";   #some text in a variable
open (CORPUS,"<$corpus") or die "erreur de texte d'origine";  
while($ligne=<CORPUS>){
$ligne=~s/^\s*//;       #if line begins with one or sev. spaces, replace by nothing
if($ligne=~m/$\./){     #if line ends with a dot,
print "$1\<br\>";       #add <br>
     }
print "$ligne";
}