Ahh, the question becomes clearer though the logic is largely similar

use strict;
use warnings;
my @records=('GAP_SPAN09 - GAP SPAN base (Scratch Testing [TSMC11] : t
+smc11_wld(sxfatd12j))',
    'GAP_SPAN03 - GAP SPAN base (DFD E2E Testing [TSPAN04] : tspan04-d
+fdint-wld(sxfamd6f))',
    'POS_WLI02 - POS_WLI02 Web Logic Integrator)');
my @record_ids;
for my $record (@records){
    $record=~m/^(\S+)(?= - )/g;
    push @record_ids , $1;
}
for my $record_id (@record_ids){
    print "$record_id\n";
}
__END__
GAP_SPAN09
GAP_SPAN03
POS_WLI02
[download]