in reply to regex needed

"If I'm trying to do an exact match..."
Exact match for what?
You didn't specify what $var contains.

Anyway, does this do what you want?

#!/usr/bin/perl -l use strict; use warnings; my $var = 'Sensor30'; while (<DATA>) { chomp; print if m/^\Q$var\E$/; } __DATA__ >Sensor30 >FooSensor30 > Sensor30 Sensor300 Sensor30 >Sensor3
Cheers,
Darren