Assuming you are reading a log file and are interested in the value of FAULT CODE and that the value is always at the end of the line if it is present at all:
#!/usr/bin/perl
use strict;
use warnings;
my $input = q{O1/APZ "GWHMSC2_R132_EP" 3233 150407 1448 BACKUP INFORMA
+TION FAULT FAULT CODE 34};
# initialize this to a numeric value so you don't get warnings
my $fault_code = 0;
if ( $input =~ m/FAULT CODE (\d+)$/ ) {
$fault_code = $1;
}
my $flag = ( $fault_code == 34 );
print "FAULT CODE is 34\n" if $flag;
exit;
__END__
The use of a flag is somewhat redundant since you can always do a test for the value where needed.
You must always remember that the primary goal is to drain the swamp even when you are hip-deep in alligators.