C:\Daten\perl>cat match.pl
#!/usr/bin/perl
use strict;
use warnings;

my $var = 'Sensor30';

while (<DATA>) {
    print if /^>?\Q$var\E$/;
}

__DATA__
>Sensor30
>FooSensor30
> Sensor30
Sensor300
Sensor30
>Sensor3


C:\Daten\perl>perl match.pl
>Sensor30
Sensor30