if ( $variable !~ /^/ ) { $exmno = 0 ); ##

##

if ( !/^/ ) { $exmno = 0 };

##

##

/^/ or $exmno = 0;

##

##

my $exmno = 0;
while(<>) {
    s/^/''/ or $exmno = 0;
    print $_;
}