my $backslash= '\\';

print "This is a backslash: ->$backslash<-\n";
print "Two backslashes: ->$backslash$backslash<-\n";
print "Two backslashes and a 't' (not a tab): ->$backslash${backslash}t<-\n";
print "One backslash and a 't' (not a tab): ->${backslash}t<-\n";
__END__
This is a backslash: ->\<-
Two backslashes: ->\\<-
Two backslashes and a 't' (not a tab): ->\\t<-
One backslash and a 't' (not a tab): ->\t<-